Now PO4 is undetectable

[lmm1967]

18 months ago I had 2 tanks (60g & 29 Biocube) with 75ppm+ Nitrates and PO4 usually higher than .7

Yesterday during testing on our 120g (replaced the 60) NO3 is below 3 (Nyos) and PO4 is undetectable (Hannah low tester). I'm fairly confident the test kits are fine as all reagents are well within expiration plus they are also used on our 30g (NO3 @ 5-10, PO4 at .71).

I'm happy with how I'm stocked and since my quarantine / holding tank is now home to a picked on goby I'd rather not add more fish.

• 3" Lightning Maroon Clown
• 3" Kole Tang
• 3" Yellow Choris Wrasse
• 2 Purple Fire Fish
• 2" File Fish
• 2" Fox Face
• 3" Speckled Hawkfish
• Sand sifting star
• Tiger Tail cucumber
• handful of snails / small blue leg hermits
• Pistol Shrimp

Tank gets fed once per day with a half dollar size chunk of frozen plus a half sheet of Nori roughly 4 times per week. Tank has about a 2" sand bed, probably 125lbs of rock, in tank flow varies anywhere from 1500 GPH up to 6000 GPH (dual XF230 Gyres that run between 40% - 100% plus 2 Tunze 6095 that run between 50% - 100%). I have no idea how much flow my return pump is actually providing.

I run a Life Reef SVS 24 protein skimmer with a CO2 scrubber and skim very dry. 5 days after cleaning out skimmer cup / locker I have about half inch of skimmate in the cup.

I did dose Nitrate a few weeks ago because my NO3 was undetectable and PO4 was .07. I got the Nitrates up to about 10 but they are slowly falling since I've stopped that dosing.

Yesterday I altered my skimmer schedule to shut it down for 7 hours during the day with the hope that may help get my nutrients a little higher. Based on how little skimmate I actually collect right now I'm guessing it's not going to make a difference.

 

[ichthyoid]

It is possible that your 2" deep sand bed has anoxic pockets which may be converting NO3 to N2 (denitrification, is a natural process, under the right conditions).

It is also probable that the 125 lbs. of rock and/or 2" sand bed are acting as nucleation sites to precipitate PO4. Especially if some or all of the rock and/or sand was new/unused.

Just curious, but I have a couple of questions-
-do you carbon dose, in any form (vodka, sugar, vinegar, bottled brand, etc.)?
-how do you manage calcium (calcium Rx, kalk, 2 part, etc.)?

 

[lmm1967]

It is possible that your 2" deep sand bed has anoxic pockets which may be converting NO3 to N2 (denitrification, is a natural process, under the right conditions).

It is also probable that the 125 lbs. of rock and/or 2" sand bed are acting as nucleation sites to precipitate PO4. Especially if some or all of the rock and/or sand was new/unused.

Just curious, but I have a couple of questions-
-do you carbon dose, in any form (vodka, sugar, vinegar, bottled brand, etc.)?
-how do you manage calcium (calcium Rx, kalk, 2 part, etc.)?

Most of the sand was brand new when I upgraded from the 60g to this 120g last February. I used dry sand and rinsed until completely clear. I seeded the sand bed with roughly 20 pounds from the 60g tank.

Rock - I've added about 60 lbs of CaribSea LIFEROCK DRY LIVE ROCK rock about a month ago. All other rock came from the 60 gallon and was about 3 years old.

I do not dose any carbon source. I had previously run a denitritor (Donovans design from R2R) but that has been offline for a good while. FYI - that device had gotten me from 80+ PPM nitrates down to under 10 on my 60 gallon prior to the upgrade - but I never had PO4 below .5 on that tank.

Calcium & ALK - 2 part dosing. Bottom line is while most of my corals are staying alive and a few are growing a little - I'm just not using all that much Ca. Currently dosing about 25 ml per day of BRS CaCl to keep it around 420 ppm. Alk I'm keeping as close to 7.3 as possible (no wild swings) by dosing about 30 ml per day of BRS Soda Ash. Mag is currently 1450 and is always above 1350. Dose by hand when it gets down but that really has only happened once.

A couple months ago (mid October) I did use chemi clean to get rid of a round of Cyano that started when we used pellets in an auto feeder while out of town for a week.

All fish are very healthy, corraline grows very well and needs to be scrapped off the side glass at least once per week.

Normal "stuff" build up on the glass requires a wipe down maybe 2 times per week.

I do not run filter socks - no reactors other than the CO2 scrubber, no carbon, no GFO or the likes.

 

[bhodges82]

I personally would shut skimmer off at night rather than day, give the coral more time to feed on particulate matter.


Sent from my iPhone using Tapatalk

 

[lmm1967]

I personally would shut skimmer off at night rather than day, give the coral more time to feed on particulate matter.


Sent from my iPhone using Tapatalk

I chose to run the skimmer through the night to keep PH more stable since I'm running a CO2 scrubber.

 

[lshin037]

Would you say dosing nitrates got your PO4 down? Im going through something similar now. My nitrates are undetectable but my PO4 is at .25-.50. And what did you use for nitrate dosing?

 

[bhodges82]

Would you say dosing nitrates got your PO4 down? Im going through something similar now. My nitrates are undetectable but my PO4 is at .25-.50. And what did you use for nitrate dosing?

I have dosed nitrate in the past to get po4 down. Redfeild ratio is 16:1 nitratehosphate, without enough nitrate the po4 can’t be consumed. In my experience, I had undetectable nitrates but high phosphates, pale corals. It worked for me.


Sent from my iPhone using Tapatalk

 

[lmm1967]

https://www.amazon.com/gp/product/B0190TQJH4/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

research mixtures and dosing amounts by searching for Randy Holmes-Farley

 

[lshin037]

Thank you, gentlemen.


Sent from my iPhone using Tapatalk

 

[ichthyoid]

I have dosed nitrate in the past to get po4 down. Redfeild ratio is 16:1 nitratehosphate, without enough nitrate the po4 can’t be consumed. In my experience, I had undetectable nitrates but high phosphates, pale corals. It worked for me.

Not to nitpick, but the Redfield ratio is the atomic ratio of carbon to nitrogen to phosphorous (106:16:1), ...not nitrate & phosphate. There is a difference in mass ratios, so adjust for that if dosing. (see stoichiometry)

Also, if there is insufficient organic carbon available (food), bacteria cannot successfully consume either nitrogen/nitrate nor phosphorus/phosphate. Regardless of how much is present.

Hence, the basis of carbon dosing. If/when doing this, begin low/slow and increase dosage gradually until desired results are achieved. I have seen others 'fly the plane into the ground' by over dosing carbon.

Also, fwiw- I use calcium nitrate on my lawn in the fall. It is readily available nitrogen/as nitrate, highly soluble and a source of calcium. The calcium is both required in Georgia clay, and useful for corals.
Reason I mention this is, sodium nitrate might alter the ionic balance if added in significant portions. Sodium can interfere in many reactions, when in excess.
Hence, I'd try calcium nitrate first & compensate for other calcium sources/dosing, as needed.

 

[bhodges82]

A little too technical for me. In my simple mind nitrogen is the same as nitrate and phosphorus is phosphate, just in different forms. There is no way to test for carbon in the system, but if the N and P are out of the 16:1 ratio formula then something is wrong. I never mentioned carbon dosing. That’s a whole different thing.

I do appreciate the heads up though, happy reefing.


Sent from my iPhone using Tapatalk

 

[ichthyoid]

I mention it because if there is no organic carbon present in the system, nitrate dosing won't work as being consumed by bacteria. They are getting carbon from somewhere...

Otherwise, perhaps it is consumed by an algae, coralline or otherwise.

 

[lmm1967]

Not to nitpick, but the Redfield ratio is the atomic ratio of carbon to nitrogen to phosphorous (106:16:1), ...not nitrate & phosphate. There is a difference in mass ratios, so adjust for that if dosing. (see stoichiometry)

Also, if there is insufficient organic carbon available (food), bacteria cannot successfully consume either nitrogen/nitrate nor phosphorus/phosphate. Regardless of how much is present.

Hence, the basis of carbon dosing. If/when doing this, begin low/slow and increase dosage gradually until desired results are achieved. I have seen others 'fly the plane into the ground' by over dosing carbon.

Also, fwiw- I use calcium nitrate on my lawn in the fall. It is readily available nitrogen/as nitrate, highly soluble and a source of calcium. The calcium is both required in Georgia clay, and useful for corals.
Reason I mention this is, sodium nitrate might alter the ionic balance if added in significant portions. Sodium can interfere in many reactions, when in excess.
Hence, I'd try calcium nitrate first & compensate for other calcium sources/dosing, as needed.

Question - something is not balanced the way I need / want it to be. I have a reasonable bio-load in the tank. Am putting plenty of nutrients into the tank. I'm not throwing all kinds of random stuff in the tank.

Whats the path for getting back in balance?

If I've got it's an in-balance of types of bacteria- dosing nitrate / phosphate may make that worse by feeding the wrong bacteria.

I could do many massive water changes - I'm not opposed to doing that I could fairly easily do 50 gallon water changes every other day - but, is that going to make it better or worse?

Just to throw this out there - this tank is in a 14' X 14' room with 2 other tanks - neither of which seem to be having troubles. All tanks with (normal) fish in them get the same food on the same schedule. That makes me fairly confident there isn't some weird airborne carbon source getting in the tank or something weird. We don't have kids or anyone in the house other than myself, wife & the dog. The sump is in an enclosed room so the dog can't be peeing in it or something nutty.

I do have an ICP test sitting here waiting - but I'd rather have not done a water change for at least a couple weeks prior to pulling a sample and sending it off and I'm not sure that is going to go very far in pointing me towards my current struggle.

I'm wondering if adding all the CaribSea Life Rock may have been a bad choice that somehow has altered the bacterial fauna in the tank. I did rinse it well and then let it sit in a barrel of fresh saltwater with a couple pieces of my established rock prior to putting it in the tank. I did very little to disturb the sand bed when I added this rock and I do vacuum the sand bed when I do water changes.

 

[bhodges82]

Is this tank stocked with a lot of coral?


Sent from my iPhone using Tapatalk

 

[lmm1967]

Is this tank stocked with a lot of coral?


Sent from my iPhone using Tapatalk

A lot? Probably not by many peoples standards.

I would say there are roughly 25 SPS pieces that would qualify as frags.

a Rock Flower Anemone, 4 SPS pieces that are roughly 4" tall, probably a grand total of 40 zoa heads and a few small acans.

enough pieces that if it would ever start growing out I think I would be happy with the tank - but right now - it looks fairly bare.

 

[ichthyoid]

I've not used Life Rock. FWIW, I'm not a fan of pre-cycled substrates, generally speaking. When was it added?

It has been my experience that a tank will self regulate/balance, within some limits, given that minimal quantities of essential foods, minerals, etc. are provided.

There is the law of the minimum, which basically states that whatever requirement is scarcest will limit growth-
https://www.encyclopedia.com/scienc...ures-and-press-releases/liebigs-law-minimum-0

Biochemically speaking, I give it what it needs and let nature do the rest.

That said, if you are driven to lower nitrates you can use a denitrifier. I have had fabulous results using one.
For phosphate, you can use GFO.
Carbon dosing, done conservatively, also yielded good results. -My $0.02

 

[lmm1967]

That said, if you are driven to lower nitrates you can use a denitrifier. I have had fabulous results using one.

I have used a denitrifier previously. It took a while for it to start working - but once it did - it was beautiful.

I could measure inbound water at 50+ppm nitrate and the outflow would be under 5ppm.

I have never had high nitrates on this tank so have not felt inclined to use it.

 

[Adam]

I don't have problems with too little PO4, I'm struggling to get it down and keep it at a reasonable level.
With NO3, until recently I've struggled to keep it under 10 but lately it's been hovering on the low side of 4.

I'm planning on testing everything when I get home and I'll update you here. You can also see the last numbers in my Apex.

If I had to guess it was the new rock. Seen too many people having issues with that Life Rock stuff from Caribsea. If the PO4 is getting sucked up then something is using it. Can you see anything growing on it, odd colored growth or white speckles?

 

[lmm1967]

I'm leaning towards bacteria.......

I just did about a 50 gallon water change on the tank. While refilling it - I put my thumb over the end of the fill hose to create some additional pressure. You know - a redneck hose nozzle. And FORCEFULLY blew new water down deep in the rock piles. Low and behold - some fairly serious gunk came flowing out of the deeper recesses of the rock work.

I've had bacteria blooms before in other tanks - and this stuff looks very very similar. Although - it's not really visible anywhere in the tank that you can see. This stuff wasn't detritus - it wasn't fine and powdery like what you get out of your sand bed. This stuff was like slightly brown snot. MMMMMMM.

I'm wondering if it's just a bacteria bloom due to all the new rock - and having areas deep down in that rock that don't get a lot of light or flow - and some odd strain of bacteria off that damn rock has taken hold in the depths of mordor.

Obviously I'll be keeping an eye on parameters for a few days and I'm thinking I may just do 50 gallon water changes every other day and see what happens.

@anit77 - BTW the WD frag is doing fine through all of this - it's not growing and PE is nothing like you have - but it's not having any trouble that I can see. Several other SPS frags are fine as well - although not growing. A plating montipora has pretty much gone away over the last 2 weeks - along with a birdsnest (yep - leave it to me to kill a birdsnest - at least it mostly dead) and things like acans are not very happy.

A few other pieces which I have zero idea of the name but they are larger branching corals - some are fading away from both the bottom & the top while others are just fine.

 

[lshin037]

@anit77 - BTW the WD frag is doing fine through all of this - it's not growing and PE is nothing like you have - but it's not having any trouble that I can see. Several other SPS frags are fine as well - although not growing. A plating montipora has pretty much gone away over the last 2 weeks - along with a birdsnest (yep - leave it to me to kill a birdsnest - at least it mostly dead) and things like acans are not very happy.

A few other pieces which I have zero idea of the name but they are larger branching corals - some are fading away from both the bottom & the top while others are just fine.

this is the exact reason Im looking into nitrate dosing. I have 5 pieces of frags and they all tell a difference story. Some are looking good and growing while others are looking good but not growing. the monti cap is growing (not the fast growth I've seen on forums and youtube) but its losing the deep brown color and getting somewhat pale. Hopefully this works. I just cant believe Im actually looking into dosing something I've tried to get rid of in my early years.