Today I had an opportunity to do some experiments with API test kits, as well as Seachem test kits. I use the Seachem kits daily at the shop. In the interest of "full disclosure" I am not a fan of the API tests. In these experiments, I did not perform the tests using the API tests, but I did perform the tests using the Seachem tests.

Joe Z provided his API tests for comparison, and we tested samples of his water. We tested his water with the API and Seachem tests.

To make the comparison fair, and scientific, we also tested samples of the reference solutions that Seachem provides with each of their test kits, with both Seachem and API test kits. The reference solutions have a stated value, so those were used as the control. Each reference solution *should* test out to the stated value, if the test kit is accurate.

We didn't test with every kit - I didn't have enough reference solution for every parameter, but some of our findings were rather alarming.

Here is what our findings were with testing Seachem's Reference Solutions which have a stated value:

pH: Stated value 8.3
Result with Seachem test kit: 8.3
Result with API test kit: 8.0 **

Alkalinity: Stated value 4.0 meq/liter
Result with Seachem test kit: 4.0 meq/L
Result with API test kit: 12 dKH (=4.28 meq/L***) The API test measures in dKH, while Seachem measures in Millequivalents per Liter, please see footnotes on conversion values.

Calcium: Stated value 450 ppm
Result with Seachem test kit: 400 ppm (tested this twice - need to investigate that further concerning the accuracy of my Seachem kit!)
Result with API test kit: 600 (!!!!!!!!!!!)

In addition, Joe brought in a sample of his water for testing.

We tested using both kits.

pH with Seachem kit: 8.2
pH with API: 8.6**

Alkalinity with Seachem kit: 3.5 meq/L
Hardness with API kit: 11 dKH (=3.928 meq/L***)

Calcium with Seachem kit: 275 ppm
Calcium with API kit: 430 ppm.

Nitrate with Seachem kit: 1-2 ppm (very difficult to tell - tested 3 times with blind interpretation)
Nitrate with API test kit: 10 ppm (with blind interpretation)

I did not have enough reference sample on hand to perform a control, but I feel that the discrepancy in results is worthy of mention. When I can, I'd like to follow this up with further comparisons using reference 10 ppm solution as a control.

**We repeated the pH tests on the control and samples TWICE because these results made no sense - the reference solution with a stated value of 8.3 tested as 8.0 on the API kit, yet Joe's water tested 8.2 with Seachem, and 8.6 with API. We even had Brian take a look at the results and he wasn't watching us do the tests, so he had no pre-conceived idea of what the result "should" be - he was blind to what samples were what, and his interpretations matched ours. I cannot explain how a water sample with a lower pH than the reference solution, tested higher with the API kit - but it did, TWICE, with a blind interpretation confirming our findings.

***I converted meq/L to dKH using the SaltyZoo conversion calculator found here: http://www.saltyzoo.com/SaltyCalcs/AlkConv.php

Conclusions: I would like to study this further - I need to procure more reference solutions from Seachem so we can do more controlled evaluations. I do need to find out what's up with my Calcium test - I tested the reference twice - its stated value is 450 and the Seachem test tested it at 400 ppm twice. Brian said he'd calibrated the test earlier in the week and it was fine. Not sure what's up with that...

Either way, API's calcium test yielded a vastly different result from the Seachem test, both on the reference solution, and on Joe's water. Joe thought his calcium was OK, but we got 275 on the Seachem test. Even if the Seachem test is off by 12%, that would put the calcium at 308 at the most. That's a far cry from the 430 the API test read. And we cannot discount that the API measured the reference with a stated value of 450, at 600 ppm. That's not even a reasonable +/- IMO.

The API pH test I can't make a scientific conclusion on because the results made no sense to us - even with an objective evaluation of blind sample results. They don't make sense. The only conclusion I can draw on this is, "inconsistent". The result is difficult to read - very subtle color changes from one value to another - which is why we had Brian take a look. His interpretation was the same as Joe's and mine.

The API Alkalinity test was pretty accurate, IMO. While it measures in dKH versus meq/L, the results were consistent and pretty similar to the Seachem test kit, based on the conversions.

The Nitrate test gave a 5-10 times higher result on API than Seachem, but without a reference to judge, results right now are "inconclusive" but definitely worth further investigation. Given that we only had one sample to base our findings on - this one needs some further work.

Those are my findings so far. I'm going to see if I can get some larger quantities of the Seachem reference solutions so I can do more testing against different test kits. Once I do procure more reference solutions I may post an invitation to have people bring in their kits for evaluation and we'll share the results.

Hope this info is helpful.

Jenn

hmmm if you werent so far, Id bring over some salifert kits to compare with. be interesting to see.

I still hate the seachem testing trays lol. and the pipettes for measuring water. if they could get away from the dropper bottles(dilute it and make it 1CC or something with a syringe) and come up with a better way to measure the powders, that would be the perfect test kit.

be careful of using a specific brand of reference for their own kits.

http://www.reefcentral.com/forums/showthread.php?threadid=1460596


from rc
"I think I can safely say Seachems reference solution is not a good reference. And their calcium test kit isn;t a very good test kit http://www.reefcentral.com/forums/images/smilies/smile.gif"

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1306742

I love seachem, some of the best salt and supplements on the market. but their test kits could use a boost big time.

I love seachem, some of the best salt and supplements on the market. but their test kits could use a boost big time.

I agree! I switched from TMPR to Seachem Reef some time ago. definitely awesome salt mix!

That's funny... every time I've tested those two against each other, I found both to be accurate. Seeing as you did not perform both tests, neither had the same standard for testing.

Based on my extensive experience in water testing, I'd have to call in to question the testers themselves. Your main discrepency has to do with calcium. I'll double check my API against Seachem tomorrow.

be careful of using a specific brand of reference for their own kits.

http://www.reefcentral.com/forums/showthread.php?threadid=1460596


from rc
"I think I can safely say Seachems reference solution is not a good reference. And their calcium test kit isn;t a very good test kit http://www.reefcentral.com/forums/images/smilies/smile.gif"

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1306742

One person's statement?

I have no reason to believe their reference solutions aren't on spec. Assuming they are on spec, any test kit that is accurate should test out at the reference value.

The Seachem calcium test is a titration test - which is IMO the best way to test (pH, Nitrite/Nitrate, Ammonia and Phosphate Seachem tests are NOT titration tests, BTW).

I will admit I don't like their ammonia test - fortunately once a tank is cycled ammonia is seldom an issue - but I have found in 7 years of using them on a DAILY basis, they are a very reliable test - and theirs is the only one I know of that even comes with a reference to calibrate the test.

Without a reference, how do you know a test is accurate or not?

Jenn

That's funny... every time I've tested those two against each other, I found both to be accurate. Seeing as you did not perform both tests, neither had the same standard for testing.

Based on my extensive experience in water testing, I'd have to call in to question the testers themselves. Your main discrepency has to do with calcium. I'll double check my API against Seachem tomorrow.

I did not do the API testing but I was standing right beside "the tester" - who asked me to verify his procedures, which I found to be correct.

I've had years of anecdotal experience with anomalous results with API tests. This was the first time I had a chance to compare them on an even playing field (ie with reference solutions with a known reference value.)

To the person above who stated that the reference solutions are unreliable - even if the stated value of the reference was "off" - all things being equal, both sets of test kits should have come up with identical results, if they were both *accurate*.

Jenn

While it's cool that you are comparing test kits, I'm just pointing out to beware of reference solutions sold to be used with their kits. That's all. and thanks for what you are doing!

Here's Randy Holmes-Farley:


http://www.reefcentral.com/forums/showthread.php?postid=11339232

Thanks, This just confirms my own "tests" I have done with API and Red Sea kits. Both those kits were either all over the place and/or i was left to interpret very slight color changes. I only use Seachem and Elos kits now.

I'll look through my science supply catalogs at work and see if I can get my hands on some "unbiased" reference solutions. :)

While it's cool that you are comparing test kits, I'm just pointing out to beware of reference solutions sold to be used with their kits. That's all. and thanks for what you are doing!

Here's Randy Holmes-Farley:


http://www.reefcentral.com/forums/showthread.php?postid=11339232


Umm - RHF did not mention anything about test kit reference solutions, only 35 PPT seawater solutions.

For the record, the reference solutions are not "sold" to be used with their test kits, they are a part of the test kit - included with the kit proper. Each kit contains a container of reference solution with a stated value. That way you can test the accuracy of the kit against the reference, or if you are having trouble interpreting the results you can test a sample of the reference for a pre-determined/known result.

Jenn

Thanks, This just confirms my own "tests" I have done with API and Red Sea kits. Both those kits were either all over the place and/or i was left to interpret very slight color changes. I only use Seachem and Elos kits now.

IME Red Sea are hit and miss. I have not done the same types of experiments (yet) but a long time ago I compared results from a Seachem Calcium (titration) test with the Red Sea one, and I was surprised that the results were consistent. I did not use a control/reference on that. I use Red Sea for FW pH and all Copper tests.

I confess I'm not a fan of the Seachem copper test - had trouble with interpreting it, but I do use the Red Sea for that - it's fairly easy to read a therapeutic dose of Cupramine with it.

I may give the Seachem test another shot though (copper).

I have not tried Elos tests so I have no opinion of those yet.

I used Salifert for a while - carried them too but nobody ever bought them - seems that at the time, everybody online touted the virtues of Salifert but nobody put their money where their mouth was (even though Salifert tests were competitively priced)... I quit carrying them when the last few expired on the shelf :(

Jenn

To be accurate, the same person must perform all tests. Also, a good reference solution is required. I've been wanting to perform some comparative tests on test kits for a long time..

Stacy, let me know if you find some good reference solutions.

Danny, I'll bring some test kits in- I have red sea mg and elso mg. Let's see how those compare while we're at it.

Who defines "good" reference solutions? :-/

I'd be more than happy to repeat the experiment, performing all the tests myself. I just need to get some more solutions.

I'd even be happy to use somebody's "approved" reference solutions. Don't know why the Seachem ones are deemed not good enough, but whatever.

I performed the experiment with an open mind - because I have done my share of bashing on API tests and hadn't used them in a long time - I wanted to somewhat satisfy myself that they had not "improved" since I'd used them. IMO they are about the same as they were last time I used them: unreliable.

Jenn

Who defines "good" reference solutions? :-/
..
I'd even be happy to use somebody's "approved" reference solutions. Don't know why the Seachem ones are deemed not good enough, but whatever...

Jenn

Solutions from a company other than the manufacturer of the test kit (an independant) would be the best choice. I don't know enough about the chemical reactions to know if the Seachem solution is "geared" towards it's test kit or not. So, using a solution by an independent company would alleviate any suspicion/possibility of this scenario.

Fair enough. I highly doubt that the references are test kit specific, but that's another fair experiment to test the accuracy versus reference solution X.

In that instance, one could compare the results of a given test kit against reference X and Seachem Reference (to put that debate to rest) as well as testing somebody's real-life water sample. The more test subjects, the merrier - as long as there is a common thread (ie a control that each test kit is measured against).

I'm game.

If folks each want to gather the kits/references and such, I'll host a science party - even if one person has to do all the testing to make it truly scientific, we can have plenty of observers for blind interpretations and such.

Jenn

This is an interesting thread. I'm curious to see the results of all you folks testing away! I purchased my test kits after reading the reviews on them on various sites on the internet (and based on availability to some extent). I use API for pH, kH, Phosphates, Calcium, Nitrites and Ammonia. I also have an Elos pH kit, and I always run both when I test. They are always within .1 of each other (for example, API is usually .1 lower, so when API is 8.0, elos is 8.1; when API is 8.1, elos is 8.2). Sometimes they both reveal the same value. I use Salifert for Nitrate and Magnesium.

EDIT
The reviews I read on the internet included ease of color charts, ease of mixing/testing, and results achieved. I was looking for test kits that would be accurate, but would also be easy to use.

Speaking of reference solutions, has anyone done a test of the accuracy of handheld PH meters? I've considered buying one (and a refractometer also), but frankly if I do it's gonna have to be an inexpensive one.

Handheld PH meters are usually dialed in with a reference solution 6,864 at 25°C
The one you used was freshly calibrated...

Handheld PH meters are usually dialed in with a reference solution 6,864 at 25°C
The one you used was freshly calibrated...

Mostly wondering if there were any accuracy issues before purchasing. Do they require calibration often?

Testing today on the Seachem reference solution of 425ppm.

API: 420-440ppm. Color change started at 420, and was complete at 440, which if you wanted to estimate within the 20ppm range, assuming 430 would not be unreasonable because the color change began at drop 21. This test kit is based on a 20ppm/drop range.

Salifert: 500ppm. This was my first time using this test. I found drop consistancy with reagent #2 hard to achieve. I stopped my first attempt because of this, and had better drip results on the second attempt.

Seachem: Cannot be tested right now. My color change indicator reagent has turned itself into a purple mini hockey puck. If anyone has one I can use, I can run the test at the next meeting.

I set out to prove that the API test kit is accurate when used properly. The kit I used is less than one year old, which is important. All bottles are date stamped. I tested within 15ppm of a known solution, which is off by 3.5% at most.

Being that this was my first time using Salifert, I'm will to allow inexperience to account for my reading that was 75ppm high, which was off by 17.6%. Has anyone else had high readings using this test kit?

If anyone has an issue with the Seachem reference sample of 425ppm, I'll be happy to test with an unbiased opinion whatever solution that you feel is more correct.

fwiw, for step 2 on the drops for salifert, my technique is to squeeze the bottle slightly in the upright position, then let it suck in as I tip it over. keeps the liquid from falling out from gravity once its flipped over, then you can squeeze for a nice even 2 drops.

Ive never tested it against a calibration solution though, never seen a calcium calibration solution actually. (never looked either to be honest)

Seachem: Cannot be tested right now. My color change indicator reagent has turned itself into a purple mini hockey puck.

Heh I have used the same description - hockey puck. Call Seachem at 1-888-Seachem and they will send you a replacement free. We find it best NOT to store the powder in with the kit proper.

Thanks for posting your findings. I did not know the date stamp on the tests we used, but I'm glad to know they are date-stamping them now - they did not used to.

Jenn

Heh I have used the same description - hockey puck. Call Seachem at 1-888-Seachem and they will send you a replacement free. We find it best NOT to store the powder in with the kit proper.

Thanks for posting your findings. I did not know the date stamp on the tests we used, but I'm glad to know they are date-stamping them now - they did not used to.

Jenn

My pleasure. I know they've been date stamping for years. It's listed in the lot number.

Red Sea has date stamped for a long time. API used to have a cryptic lot number when I used those tests. I quit using them when I found wacky results and switched to another test...

Do they state what the expiration date is? (Red Sea has an EXP. date, not a "born on" date!)

Seachem has lot numbers and claim a shelf life of 5 years. I burn through tests, I'm lucky to keep some for 5 days, or maybe 5 weeks (for CA etc).

Jenn

How long ago were you using their tests?

Years ago. The company rep calls on me every now and then - I have continued to read bad press about these kits, that was consistent with my own experiences (ie no improvements). I addressed the issues with the rep who has "never heard" of any anomalies with those kits. Look on just about any hobbyist site, and somebody will report anomalies with those kits. So I won't carry them, and I surely don't recommend them.

Jenn

I've never really had issues with API's nitrite, nitrate and ammonia test kits. The calcium seems reasonably accurate too. Though I just may have had a good set of test kits. Now their pH tests are a total joke. Mine would show a pH of around 8.2. I took my water into Marine Fish and was told me the pH was low. They use a test strip and it was showing 7.8 or so.

For Xmas this past year, the wifey gave me a hand held electronic pH tester. It actually showed the strips (non API) were more accurate than API when it came to pH!! :eek:

Was the pH tester calibrated?

Strips, IMO are far less accurate in general, than even the most unreliable test kit. A strip might rule something in or out but precision is not usually found in strips. At least in my experience.

Jenn

Was the pH tester calibrated?

Strips, IMO are far less accurate in general, than even the most unreliable test kit. A strip might rule something in or out but precision is not usually found in strips. At least in my experience.

Jenn
At that time, no it wasn't calibrated. But I just did (ok it was like an hour ago) and it was reading low by 0.1. It is now calibrated. I don't have the API pH test kit anymore as I had thrown it out quite a while ago.

I however still had some test strip so I thought I'd test my main display tank. The test strip (Quick Dip brand) a bit over 7.8. The only problem with the strips is that it goes from 7.8 to 8.4 in the color chart. All you can really tell is that it's in between the 2.

My pH meter reads (after it was calibrated) 8.10.

My experiences with the API dropper tests is that the pH never varied. I know that is highly unlikely. pH varies even throughout the day but API always read normal.

Within my ability using Seachem 425 mg/L reference solution:

API: 420-440ppm. 96.5% Accurate

Salifert: 500ppm. 82.4% Accurate
(2nd test): 500ppm 82.4% Accurate

Seachem: 430ppm. 98.8% Accurate

I also ran some Magnesium kits while I was at it. Within my ability using a Seachem reference solution of 1180mg/L. I also tested an aquarium sample to see the different between the kits outside of a known reference.

Seachem:
Reference: 1125ppm. 95.3% Accurate
Sample: 1215ppm

Red Sea:
Reference: 1500ppm 78.6% Accurate
Sample: 1500ppm

The difference between results the reference and sample was 90ppm, which is a difference of about 7%. I conclude from this, that the reference solutions from Seachem are accurate. Talking with Jim at Seachem today, he informed me that the solutions are tested by a third party using methods that assure accuracy.

Elos: This kit annoyed me. Not only do I not agree with the way the test is structed, as it appears you're creating the titrant within the vial, I could not get a result from it. It may be that I have a bad kit. It is not expired. I ran the test on two samples with the same result: The final color change did not shift from pink to purple, it infact remained green. Any ideas? In addition, if your test kits costs that much, get a better translator.

Great info, Danny! Thanks for posting that :)

Honestly with a hobby grade test kit, there's bound to be some +/- . Not too many hobbyists invest in truly scientific grade testing kits (myself included).

Jenn

Testing comparison:

I was not happy with the wide variation I was getting between my API test kit and my Jungle Quick Dips and thought that it would be wise to get some independent testing. I loaded up a quart of tank water, grabbed my API kit, Quick Dip and Hydrometer and headed over to Imagine Ocean.

Jenn was there and she was intrigued by the idea of another testing comparison and was completely on board to work with me on this experiment. :D

On to the results...

(1) Specific Density
- my Hydrometer - 1.023
- Jenn's Refractometer - 1.023
So far so good. :tongue: We matched and I feel good that my Hydrometer is currently working perfectly. I'm still buying a Refractometer as it is too fun of a toy to pass up.

Please note that all of the following tests were performed by Jenn with me playing lab assistant. Where appropriate we had three sets of eyes doing an independent blind grade of the results.

(2) pH
- API - 8.1 (Bill) 7.9 (Jenn) 7.9 (Brian)
- Jungle Quick Dip - 8.3 (Bill) 8.2 (Jenn) 8.1 (Brian)
- SeaChem - 8.2 (Bill) 8.1 (Jenn) 8.1 (Brian)

(3) Ammonia
- API - 0.75 (Bill) 0.75 (Jenn) 0.50 (Brian)
- Jungle Quick Dip - n/a, the Quick Dip does not measure Ammonia
- SeaChem - 0.7 (Bill) 0.4 (Jenn) 0.4 (Brian)

(4) Nitrite
- API - 1.0 (Bill) 1.0 (Jenn) 1.0 (Brian)
- Jungle Quick Dip - 2.0 (Bill) 2.0 (Jenn) 1.5 (Brian)
- SeaChem - 4.0 (Bill) 2.5 (Jenn) 4.0 (Brian)

(5) Nitrate
- API - 15 (Bill) 15 (Jenn) 15 (Brian)
- Jungle Quick Dip - 20 (Bill) 15 (Jenn) 15 (Brian)
- SeaChem - 1.5 (Bill) 2.0 (Jenn) 2.0 (Brian) - After looking at these results I'm not sure if the Nitrate scale used was the same.

(6) Alkalinity
- API - n/a, API does not test Alkalinity in my set
- Jungle Quick Dip - n/a, we got a funky blue color on the test strip that had no assigned color to grade against. We tested the sample twice and got the same n/a color both times.
- SeaChem - 3 (Jenn) - This was a titration test so there was no blind evaluation.

(7) Magnesium
- Red Sea - 1200 (Jenn) - This was a titration test so no blind evaluation.
- SeaChem - 875 (Jenn) - This was a titration test so no blind evaluation.
There was such a big difference here that we pulled out the reference sample from SeaChem with a known value of 1080. We tested the Red Sea test against it and came up with a value of 1300. We tested the reference with the SeaChem test and came in right at 1080. To make matters worse for the Red Sea kit was that it was almost impossible to fill the syringe as the chemical bottle to draw from had a dropper top. :o It took two of us and a lot of spilled reagent to get the syringe filled properly. Aggravating the problem was the issue of the syringe and the supplied needle not coupling correctly. The test was, for all practical purposes, unusable. When we finally got the syringe filled the test seemed to overstate the Magnesium by a material amount.

(8) Calcium
- Sera - 300 (Jenn) - This was a titration test so there was no blind evaluation.
- SeaChem - 300 (Jenn) - This was a titration test so there was no blind evaluation.
We also tested the Sera against the SeaChem reference liquid with a known value of 450 and it matched perfectly. I have a lot of confidence that both the SeaChem and Sera gave an accurate reading. The difference between the two is that you must remember the number of drops with Sera while you use a syringe for measurement with SeaChem.

So, what did I learn?
1. User judgement plays a factor as the three of us "graded" the results differently.
2. I like the little white tray that SeaChem uses so that you can do most of your tests at once without fiddling around with vials.
3. The Red Sea Magnesium test is not going to work for me. Maybe I got a defective vial and syringe but as it stands, it is unusable for solo testing. Even when we got it to work the results were very suspicious.
4. The Sera test was right on and very easy to use even though the spoon for adding the powder was a bit tricky. I like the measuring spoon better with SeaChem but that is a pretty minor point.
5. I'm not a big fan of the Quick Dip strips as they are harder to interpret and probably only good to give you a quick read of basic tank parameters.
6. The color cards with SeaChem are awesome. SeaChem uses a white card with a "window" that has a color strip threaded through it. You can very easily isolate the right color vs. the color cards that API uses. I do wish that the "units" for the hash marks between the numbers clearly marked.
7. Hydrometers can give you a funky reading if you aren't careful about air bubbles.
8. Light plays a factor, grade in a well lit place with natural light if possible.
9. Overall I have more confidence in SeaChem than API or Quick Dips. SeaChem seems to be more consistently on target.

A huge :thanks: goes out to Jenn and Imagine Ocean for helping me with this. You are wonderfully patient, especially since this was supposed to be your day off. :D

[I also posted this over in my tank build thread at http://www.atlantareefclub.org/forums/showthread.php?t=29195]

Thanks for the post. I did my own test with seachem and red sea kits last week and ran into the same type of results as you did. I also compared a seachem mag kit with an elos mag kit. The elos read 1250 vs the seachem which read 1375. After running them both against the seachem reference solution the difference was the same. Elos read 100 to 125 ppm low against tank water and reference solution. although those results are fairly close I'm going to stick with the seachem kits. I like the supplied reference solutions. That being said, i did run into a bad seachem alk test kit Saturday. The reference solution was supposed to read 4mgl and it came out to 8mgl. I ran the test twice with the same result.

If you contact Seachem, they will replace the bad one for you.

888 Seachem.

Jenn

(7) Magnesium
- Red Sea - 1200 (Jenn) - This was a titration test so no blind evaluation.
- SeaChem - 875 (Jenn) -

To make matters worse for the Red Sea kit was that it was almost impossible to fill the syringe as the chemical bottle to draw from had a dropper top. :o It took two of us and a lot of spilled reagent to get the syringe filled properly.

(8) Calcium
- Sera - 300 (Jenn) - This was a titration test so there was no blind evaluation.
- SeaChem - 300 (Jenn) - This was a titration test so there was no blind evaluation.


A few things.

1. The isntructions for the Red Sea Mg say you have to remove the dropper top on the reagent to fill the syringe. They put it in there to keep it from spilling in shipping. That will make your life easier. :)

2. This is the interesting thing. Take your Seachem Ca and Mg and add them together and what do you get? 1175ppm. That's almost exactly what Red Sea read on magnesium.

A magnesium test kit will test calcium, strontium, and magnesium as positives. I wonder if the Red Sea test kit isn't precipitating out the calcium as it should. More testing is in order. We ignore Sr because it's NSW level is 8ppm, which is negligable on the huge magnesium scale.

3. API is in most respects decent enough for regular testing. Seachem is more accurate, though significantly more complicated and expensive. Being that API provides a lot of decent testing for a low price, I think it makes a great test for someone just getting into the hobby. It's great for getting it into the hands of someone that wouldn't shell out $30 for the more accurate test.

4. Regarding alkalinity- It's pretty hard to mess up building an alkalinity test. They all work in the same fashion, and that is determining how many drops of acid z it takes to get Sample x to pH y(typically pH 4 or 5). Again, for the price it makes a handy tool to double check your other kits. Seachem has the extra step to determine how much of your alkalinity is made up of borate, which while great at maintaining pH, does nothing for coral skeletal growth.

5. Part of the reason Seachem makes their tests more complicated is to force the user to take the time to do it correctly. Certain reactions have to occur and they only do it within a certain window of time for the test to be accurate. Seachem makes it difficult for the user to rush through the test, and by using volumes instead of drops counted assures that uniform drop size(in most cases) is not essential as it is with API.

3. API is in most respects decent enough for regular testing. Seachem is more accurate, though significantly more complicated and expensive. Being that API provides a lot of decent testing for a low price, I think it makes a great test for someone just getting into the hobby. It's great for getting it into the hands of someone that wouldn't shell out $30 for the more accurate test.

Since you cut and pasted, so am I (from Bill's thread).

Here's where I need to disagree with you. Seachem's basic tests are much SIMPLER than API. Have you used Seachem's Marine Basic test kit? I performed tests for Ammonia, pH, Nitrite, Nitrate, Phosphate and Alk before Bill had filled a test tube for the API. Never mind invert this twice, shake that for 1 minute...

Seachem test: fill the little test tray with water samples (up to 6). pH: Add one drop of pH reagent, read the result. Nitrite: add one drop of nitrite reagent, read the chart. Nitrate: use the same nitrite test, add one little measure of Nitrate reagent, read the chart. Alk - number of drops/2 (like many tests). Phosphate: 2 drops of reagent 1, 1 drop of reagent 2 - read the result. You can literally have all those tests done in about 1 minute - except ammonia where you have to wait for the test to develop (I admit there could be a better Seachem ammonia test, but once a tank is stable, it's rarely needed).

As for your notion that Seachem is "$30 more"... well I looked at Race's site and Seachem is $10 more for the basic test. Seachem's basic includes ammonia, pH, alk, nitrite, nitrate, as well as reference solutions to verify the accuracy each. API has ammonia, pH, nitrite, nitrate - NO ALK.

The Seachem Phosphate test is sold alone, or as part of the "Reef Special" bundle which includes Phosphate, Silicate and Iodide. That bundle sells for the same price as the basic.

API has a Reef kit that tests for Nitrate (duplicates the master test), KH (Alk), Phosphate and Calcium. It sells for the same price as the API basic kit.

Seachem's calcium test kit is more expensive, there's no doubt about that. It sells as a single kit, and while it's a bit pricey, it does a LOT of tests. At my store's price it works out to about .25 per test.

Seachem's Magnesium test is also spendy but also contains tests for carbonate and borate alkalinity if you choose to monitor those, those tests (titration tests) are included.

Seachem also makes a Strontium test - I've got one but I don't think anyone has ever asked me to test Strontium.

As for the Red Sea MG test - both of us tried to remove the dropper top from that reagent bottle and neither of us could. Also the plastic syringe tip did not fit snugly on the syringe and there was no thread to screw it on, so unless somebody was holding the syringe up to the tip (and there was spillage) - that whole setup was completely and totally NOT user friendly.

IMO the Seachem tests are a good value. There's no point in spending money on a kit that isn't accurate. We've found the API to be all over the map, as well as being very difficult to interpret.

Jenn

So you're saying you disagree with me, agree with me, and that you're wrong. More on this later, I have to get some salt mixing.

No, I'm saying that I disagree that Seachem are more complicated and "$30 more". They are simpler, and on one popular etail site, they are $10 more. They also include an extra test (comparing both "basic" test bundles).

I did acknowledge that the Seachem CA and MG tests are expensive, but I also noted that the CA test works out to $0.25 per test even at my retail price (which is likely to be a bit more expensive that Race's site). So in the big picture, it's not that expensive to get a decent, accurate test kit.

As for "I'm wrong" - I'm not sure why you made that statement, other to be inflammatory.

Jenn

Elos: This kit annoyed me. Not only do I not agree with the way the test is structed, as it appears you're creating the titrant within the vial, I could not get a result from it. It may be that I have a bad kit. It is not expired. I ran the test on two samples with the same result: The final color change did not shift from pink to purple, it infact remained green. Any ideas? In addition, if your test kits costs that much, get a better translator.

Danny, it sounds like maybe you didnt pour out the solution once you got the first reaction to occur. If you add the last 2 reagents to the previous test, it wont work and you get a strange green liquid. I made the same mistake.

After you add the reagent to the first 3ml of water, and get it to change colors, you pour it out and start with a fresh 3ml of water to do the second reagent test. Then you subtract the two seperate test results and multiply by 20 or whatever it is.

Danny, it sounds like maybe you didnt pour out the solution once you got the first reaction to occur. If you add the last 2 reagents to the previous test, it wont work and you get a strange green liquid. I made the same mistake.

After you add the reagent to the first 3ml of water, and get it to change colors, you pour it out and start with a fresh 3ml of water to do the second reagent test. Then you subtract the two seperate test results and multiply by 20 or whatever it is.

Yeah, that's exactly what I did. I found out already and haven't had a chance to retest.

You can literally have all those tests done in about 1 minute...

I would be careful how you advertise your testing procedures. Testing at that speed greatly increases the risk of error. Water testing is not a race.

As for your notion that Seachem is "$30 more"... well I looked at Race's site and Seachem is $10 more for the basic test.

But you're not selling them at internet prices, are you? What would the difference be at your store?

We've found the API to be all over the map, as well as being very difficult to interpret.

This is where you're wrong. You've found yourself to be all over the map, not the kits. I've had no issues testing consistently with API kits. I'm not saying they're better that Seachem, I'm saying they're good enough and certainly not inaccurate.

If you look at your results between the testers, you were more consistent with API than Seachem. Look at your numbers again and you'll see.

pH
- API - 8.1 (Bill) 7.9 (Jenn) 7.9 (Brian) 66.6% Consistent
- SeaChem - 8.2 (Bill) 8.1 (Jenn) 8.1 (Brian) 66.6% Consistent

NH3
- API - 0.75 (Bill) 0.75 (Jenn) 0.50 (Brian) 66.6% Consistent
- SeaChem - 0.7 (Bill) 0.4 (Jenn) 0.4 (Brian) 66.6% Consistent

NO2
- API - 1.0 (Bill) 1.0 (Jenn) 1.0 (Brian) 100% Consistent
- SeaChem - 4.0 (Bill) 2.5 (Jenn) 4.0 (Brian) 66.6% Consistent

NO3
- API - 15 (Bill) 15 (Jenn) 15 (Brian) 100% Consistent
- SeaChem - 1.5 (Bill) 2.0 (Jenn) 2.0 (Brian) 66.6% Consistent

That's API's 83% consistency to Seachem's 66% consistency in your hands. This reinforces my argument that it's more the hands of the tester than it is the test.

It should be noted that there's huge flaw in your test in that you didn't use API designations according to the color card on some test, but guessed at the inbetween.

I'm not trying to convince you that you should be using API. I want you to understand that they're reliable test kits and don't deserve the bashing you're giving them.

Prove to me that there are error with the kits by having the reagents themselves and the procedures used verified by a lab. Like I said, all you're testing right now is your ability to test.

I know it's not a race. My point was, it's easy to complete Seachem tests because they are simpler to perform than the API which require shaking this for X seconds etc. With Seachem you do not need to do that. You do need to wait a few minutes on some to get a solid result, but my point was to respectfully disagree that Seachem tests are more difficult than API to perform.

No, I'm not selling at Internet prices. I don't stock API. Based on the wholesale prices of the API tests, they would be about $5 less in my store, using the same formula to determine price. That's for the Saltwater Master Test Kit (API) versus Seachem's Marine Basic. If you consider that Seachem's test kit also includes an alkalinity test which API does not, it's actually a better deal on the Seachem because you'd have to either buy a separate KH test from API, or a Reef kit from API and you'd have duplicate nitrate tests (one in each kit).

Concerning the results that you quoted back - on Bill's water sample, we really do not know what the *true* value of the sample was - so while there were discrepancies in how we all interpreted them - we really can't conclude who was right - or if anyone was right. The only way to do that was if we'd tested all known references - and I didn't have enough reference solutions on hand to repeat that test as we did at the beginning of the thread. On the API cards sometimes we achieved a result that looked "in between" - ie the color card has a value for 8.0 and 8.2 and the test tube looked too light for one and too dark for the other, so we "split the difference". The Seachem color charts are graduated so the darker the color, the higher the result, except with the titration tests, which leave little room for mistakes in interpretation. I find with the API tests, some colors are very close, but with very different values, and thus, makes it more difficult to interpret.

There was another thread recently where the OP asked what sort of lighting should he read his results under? That's a good question really. I've always used fluorescent overhead lights and placed the card and tube against a white background - and even with that it can be a tough call sometimes.

With the Seachem test, you already have a white background (the testing tray) and graduated colors on a slide-through window that lets you slide the chart through a narrow window until you can see a good match. No, not as easy to interpret as a titration test, but more user-friendly than many of the other brands I've played with over the years. And if you're iffy about whether you're reading your result right, you can always test a sample of the reference to compare - and you can do a side-by-side comparison using the same test tray.

I'm not the only one who bashes API test kits. They have had a questionable reputation for years, and on many forums. So it's not "just me". I had firsthand bad experience with them - particularly when the reagent goes bad - in the good old days they did not have an expiration date, and they seem to have a very short lifespan - and who knows how long they sat in a wholesaler's warehouse or store shelf?

Seachem does not have expiration dates either but they do have lot numbers and they will replace "bad" reagents for free - just call them at 888-Seachem. They claim a shelf life of 5 years. I've never put that to the test - I go through test kits at least one a week if not more, of each type as we do a lot of testing here, on our own systems as well as clients' systems.

And I'm not saying you should switch either - but I will also point out that Seachem is a Georgia company. They are based here in Madison, GA. They provide free training to any retailer who wants to partake in it, and it's not just "salesmanship" of their products - it's the science behind it and *why* certain products work in certain ways.

As long as their product is of equal or better quality than someone else's, I'd sooner keep the money here at "home". While this has nothing to do with the accuracy of their tests or whatnot - I thought it also worthy of mention. Support local businesses.

If I didn't think their product was worthy, I wouldn't sell it, let alone use it. I believe in their products and I'm pleased to use and recommend them.

Jenn

Why don't me or Steve see if the GAI will test some water for us? I'm quite confident whatever they are using is probably pretty darn accurate, no?

It's not so much about the "water" - it's about whether the test kits (or the tester!) are accurate.

The only way to really do that is by testing "water" with a known value (ie Seachem's reference solutions) - if a kit consistently tests a reference sample to the known value, it can be deemed to be an accurate kit. If it tests consistently different from the known value, it can be deemed to be inaccurate. That was what I was attempting to do in the first post of the thread - I had someone come in with his API tests and we conducted tests on both his water (of unknown values) as well as Seachem's reference solutions.

Someone called the validity of the solutions into question but someone else confirmed that those references are verified by a third party lab.

So, if, for example... if you are running a calcium test with a sample with a known value of 450 and the test kit shows it's 600, then the test kit is way off.

Jenn

You're forgetting that I invalidated those test and verified the accuracy of the reference solution.

I performed the exact same tests as you with accurate results. Go back a read my posts.

I'm a huge advocate of Seachem, but I'm not going to bash another company because of it. If your last argument is, 'I'd sooner keep the money here at "home"', I can only lose all respect to any previous argumnt.

It seems to me that you're just not willing to accept that I can perform the tests with high accuracy and you cannot.

Jenn, after seeing the equipment they have in the water testing facility, I'd trust their results of my water AS a reference solution! :) See which tests show the same as their results and that's the test I would use.

Danny - keeping the money at home is not my sole reason for advocating Seachem tests, if you read my post, I qualified it with deeming the products worthy.

We can keep on picking flies at one another all we want, it's not going to change your mind or mine - so let the reader take from this what they will. As I mentioned, I'm not the only one who has ever complained about API tests... check out many threads here where somebody gets wacky readings, and other posters as well as me will ask the first question, "What brand of test kits?" and if the answer is API, the ensuing recommendation is to have the results verified using another brand of kit.

If I was the only one here (or anywhere else online for that matter) questioning the accuracy of the kits, then I'd be fair game. Fact is, I'm not. There are many posts on many forums that call the accuracy and shelf life of API tests into question and I've even had the discussion with the manufacturer's rep.

If you are satisfied that they are accurate - more power to you. But I did dispute your claims that the Seachem tests are "$30 more" than API, and that they are more complicated to perform than the API, which they are not. I stand by that.

I accept that my interpretations are open to criticism, and so are others', including yours. It also stands to reason that *any* test of any origin, can be misinterpreted because of color change subtleties. Titration tests are the most accurate, IMO, and have the least margin of error because of the distinct color change.

Jenn

Yeah, yeah. I have too many other arguments going on right now anyway. :)

One last thing, however. You're misquoting me:

your claims that the Seachem tests are "$30 more" than API

I said $30. Not $30 more. I base this on the calcium test kit (http://www.marinedepot.com/ps_viewitem.aspx?idproduct=SC4115&child=SC4115&utm_source=mdcsegooglebase&utm_medium=cse&utm_term=SC4115&utm_content=SeachemReefStatusCalciumTestKit&utm_campaign=mdcse&site=google_base), which is $30+ after shipping. Compare that to API Calcium (http://www.marinedepot.com/ps_ViewItem~category~Aquarium_Pharmaceuticals_Salt water_Calcium_Test_Kit_Calcium_Test_Kits_for_Saltw ater_Aquariums~vendor~Aquarium_Pharmaceuticals~idP roduct~AP3137~idCategory~FITKCA.html), which I tested to be almost as accurate as Seachem.

So there! I'm done and happy testing!

I acknowledged that the Seachem test was significantly more expensive than API - and I apologize for the misunderstanding on my part.

I have to disagree with you however, on the accuracy. In our little test, the API registered 600 on the Seachem Reference with a known value of 450. My testing of the Seachem test on the reagent came up with a discrepancy also. I since changed to a new bottle of titration solution which tests spot on with the reference at 450.

I have another customer with an API test kit who was reading 530 on his calcium with API, and we tested it with Seachem and it was 275. You can pick at my methods all you like, but in 2 weeks I had 2 different customers with 2 different tanks, whose water came up WAY different using an API test, versus a Seachem test whose accuracy had been checked with a known reference.

I'm just sayin'...

And I've had that happen plenty of times too - just those two instances very recently. Two different people, using the same brand of test, and getting skewed results. If it's a "user error" then it's a consistent user error.

Jenn

ck this out http://kb.marinedepot.com/article.aspx?id=10833&utm_source=mdnl20090123&utm_medium=mdemail&utm_term=mdnl20090123TestKitsArticleraj007@charter .net&utm_content=mdnlTestKitsArticle20090123&utm_campaign=mdnl

Thanks for posting that!

I just skimmed it a bit but I'll take a closer look in the morning - I'm outta here!

Jenn

I guess if you repeat the same thing enough times without backing it up anymore, you'll eventually be right, Jenn.

If only the test in that link had used known quantities it would be a lot more worthwhile.

sorta related to this topic, I did comparison testing of Tetra and API and some Salifert tests trying to figure out a dosing issue.
Figured why not, I had an API kit and a Tetra kit to do a head to head with.
Did 4 sets of tests, each set with a duplicate. Average between each test was averaged or remained the same value. Two persons independently tested and recorded the results.
Did run out of reagent for two Tetra kits on the second pass, but the baseline difference was close.

I think what some are missing in this "great debate" is that new reefers will always pick out the cheapest test kit. They want to save their money for fish and corals.

But the bigger issue is to get new hobbyists testing. Expensive test kits means they "run a sample to the LFS" rather than test themselves.

Even a "bad" test kit will give us an approximation when trying to help a hobbyist with an emergency on Saturday night when the LFS is closed.

API isn't that far off the mark most of the time and it's cheaper than the others. Requiring the "top of the line" means fewer hobbyists are testing.

Interesting thread............wether true or not, API test kits are regarded as about the worst (accuracy wise-deserved or not) test kits on the market by Reefers, if you've done any reading on RC, R2R or others. I have had this opinion myself for years.

If it is true:

Then Aquarium Pharmaceuticals should revamp their test kit line with more accurate solutions that give consistent reults.

If it is not true, and is a result of User error:

Then Aquarium Pharmaceuticals should revamp their test kit line and make them more user friendly, because consistent User Error is indicative of poor instructions, or poor reagent holding containers, or poor measuring instruments, etc. If so many Testers have problems completing the tests using the API Test kits and Instructions as packaged, then that is on API just as much as the Tester. API is only shooting themselves in the foot by not changing things and making their kits easier to use by the Public, assuming the kits are accurate. Hard to use kits just perpetuate these rumours, assuming the kits are accurate.

Either of the above being true, it really requires some action by API to make their Tests either easier to use, or more accurate and consistent.

Dave

You're right David. I spoke to the rep myself about this - fell on deaf ears.

It's probably the number 1 selling kit on the market though - because it's about the CHEAPEST.

I don't carry them (never have, and I won't either) but almost everybody else does, and if the average person is weighing choices in a store (or even online), it all comes down to price, unfortunately.

My auto mechanic used to have a sign above his counter that said:

"The bitterness of poor quality lasts long after the sweet price is forgotten."

Jenn

FWIW I've tested API a number of times against other sets of calcium tests and always found API to be right on. I think its all about having uniform drops and not allowing water to spill out when shaking the vial. I've also never had much luck with seachem tests kits, In my experience Seachem Alk, Cal, and MG all test significantly lower than Elos salifert and API which all test consistently at the same values. This is just my opinion based on what I've seen comparing these test kits so to each his own i guess

Patrick - I'm not trying to argue - I promise.. but how do you know it's "right on"? Are you checking the kit with a known reference? That's the only way to know if *any* kit is testing true or not.

Only one brand that I know of supplies a reference solution.

Jenn

FWIW I've tested API a number of times against other sets of calcium tests and always found API to be right on. I think its all about having uniform drops and not allowing water to spill out when shaking the vial. I've also never had much luck with seachem tests kits, In my experience Seachem Alk, Cal, and MG all test significantly lower than Elos salifert and API which all test consistently at the same values. This is just my opinion based on what I've seen comparing these test kits so to each his own i guess

IMO keeping the water from spilling during skaking the vial could only be accomplished by gluing it shut. :D
Yes, I was one of those who started out and figured all test kits were the same and bought the cheapest. I'm slowly replacing the kits as I can, because without getting involved in this peeing contest, there have at least been enough questions raised by many people that I don't really trust the numbers, and if I don't trust it I don't want it.

Interesting read everyone!

On a side note, I would agree that titration tests are the best. Although when you are color blind (red-green) and the test goes from pink to blue, it can be challenging. Honestly, I have to ask my four year old daughter to help.

Me: Is it blue yet?

Her: No daddy, I told you it is still purple!

Thought you could use a laugh.

Now, tell me, which company shells out to verify their kits?

*cough*http://ts.nist.gov/MeasurementServices/Calibrations/policy.cfm*cough*
:w00t:

Yup, nothing like Elos. The only hobby grade (except DD Merck) that I trust from one kit to another, time after time. Of course, api alk is good and api calcium is fine. But I still use Elos for those, too. The extra couple bucks gives me peace of mind.

Now, tell me, which company shells out to verify their kits?

I give, who?

IMO keeping the water from spilling during skaking the vial could only be accomplished by gluing it shut. :D

Are you shaking them or inverting them repeatedly? There's a big difference there.

Are you shaking them or inverting them repeatedly? There's a big difference there.

Inverting. The caps always leak a little no matter what I do. The leakage is very minimal, though, so I don't think my results are getting skewed.

Leave the cap off,put your thumb over the end and they work great.

Leave the cap off,put your thumb over the end and they work great.

That can skew a result, especially pH.

That can skew a result, especially pH.


That's why I use the caps, but it seems like no matter how hard you press the caps on they dribble a little bit anyway. Once I pick up a pH "pen" meter, I'll probably only use the API nitrate test routinely anyway.

I made that observation too - inverting it with the cap on, it leaks. Got funky reagent stuff all over my hands (and washed off really well after wards - it felt slippery). I am pretty sure at least one of those reagents contains hydrochloric acid (and I'm sure they aren't the only kit to contain harmful chemicals - Seachem's strontium test comes with gloves...)

If I can avoid getting that sort of stuff on my skin - I do.

Jenn

Sure

I know this discussion is rather dated, but I just stumbled across it and wanted to clarify our process of validating our tests:

When we make up a reference solution for our kits, they are sent off to an independent lab where they perform an ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometry for anyone who cares) analysis. They send us the numbers as our reference value to list, but we don't stop there. Next, we use an AA Reference Standard with a known value for that particular element and adjust our titrant to match up with this reference. We then use our titrant to test our made up reference solution. If, at the end of all of this, our titrant does not match up with both the AA standard and our reference, we start over again.

I am not quite certain as to why anyone would feel that our references were somehow adjusted to only test that solution accurately, but hopefully this clears it up. I find it intriguing that the company who does put the effort and money forth to provide a reference would be the one in question. Odd...