View Full Version : 90% water change

03-31-2011, 10:23 AM
I wanted to start this thread for anyone that was interested. It's been about two months since my crash thread (, with no real progress. Granted, I've been working ~100-120 hour weeks (seriously) for the past several months, so I haven't done much recently to make a difference. In fact, I haven't done much more than work.... :(

I do know that moving the corals to another tank (with a dip in CoralRx in between) seemed to do wonders for the coral - every one that was moved looks great. With that in mind, it's likely not a bacterial infection that I want to risk antibiotics on.

I have tried adding carbon and some Poly pads (, but haven't seen any difference. I'm still not willing to cut out my corals out and start from scratch.

So... I'm going to try one more thing before I reach that conclusion - doing a ~90% water change. Normally, I'd never consider doing something so disruptive, but since the corals are stressed and doing pretty badly, I'm not sure I can do worse.

I've got a 240g DT, 300g DT, and 120g of actual water in the sump. I've only got volume for 300g of made up saltwater, so I'll have to do things in batches. Disconnecting the 300g and then draining the sump and 240g display will go first, and then I'll make up another batch of water and do the second tank. Either way, it won't be terribly fun.

I'll try to take pictures along the way- it should be interesting...

03-31-2011, 10:32 AM
Chris, I've got a couple of 50g drums if they would help.

03-31-2011, 10:34 AM
Thanks for the offer. I'm honestly not sure if I can manage much more than what I've got already....:confused2:

03-31-2011, 10:35 AM
Wow Chris, that's a big undertaking for sure. Good luck and let us know if you need help or anything.

03-31-2011, 10:42 AM
Ive done similar multi tank large changes like that.

It will take a few days, just make sure each DT has a heater and some power heads so they can stay disconnected for a few days without going stagnant.

Make sure you have the water conditioned and heated before you start.

Do the largest display first, drain as much water as you possibly can and refill it, again making sure you have a heater and power heads(or closed loop) running.

Mix up the next batch and repeat for the other displays. Once they are all done do the sump and then start everything back up again, but make sure you have the return pumps turned down real low so things can equalize over a day or so.

After that turn everything back up and do an other 30%ish water change for good measure and youre done.

03-31-2011, 11:00 AM
You know... after reading through my own post, now I'm wondering if I should just go through the hassle of taking everything out, dipping it, putting it in a QT tank, and essentially starting the tank over. It'd give me a chance to kill the sudden infestation of aptasia and other pests as well...


03-31-2011, 11:04 AM
You know... after reading through my own post, now I'm wondering if I should just go through the hassle of taking everything out, dipping it, putting it in a QT tank, and essentially starting the tank over. It'd give me a chance to kill the sudden infestation of aptasia and other pests as well...


This is what I was thinking. Not much difference, really, in a 90% change versus a 100% change. I truly hate that you are experiencing all this trouble. :(

03-31-2011, 11:33 AM
Chris - Hated to hear about your tragedy and losses. I recently lost my entire system, no where near the scale or yours, but its depressing all the same. I ended up tearing the system down and am in the process of killing of the live rock all together and re- seeding it for a new tank. Too many pests and forms of algae to do anything else with it.

My sympathies to you, sir.

03-31-2011, 11:58 AM
Ouch. LMK if you need help.

Ralph ATL
03-31-2011, 12:13 PM
good luck! either way, it should help!

03-31-2011, 12:24 PM
Again, I am so sorry you are having these issues, only complicated by your demanding work schedule.

You may consider salvaging the corals/livestock you can in your separate QT system, and then what about an intentional massive ozone ovedose in your main system to take care of the pests? Borrow an extra O3 generator or two and nuke the main system?

Trying to think of ways to treat the DT water/tanks without you having to do a lot of physical work.

03-31-2011, 12:38 PM
wow, good luck on the venture, i can add that i have done fairly large water changes. I have a 40g breeder with a 20g Long for my sump. I changed about 30-35g which is only about 60 percent water change but that is all i have on hand at one time is that much.. plus, factoring in all my live rock and i don't really fill up the sump slap full of water, so its not likely a full 60g total volume, so i have probably done a fairly large amount on my system either way.

i only have done with 3-4 times in the 2.25 years i have had the tank.

03-31-2011, 12:58 PM
I'm challenged with the same issue, albeit on a *much* smaller scale. Right now, my tank is a place where corals go to die very slowly. I've been doing overly large water changes with little benefit so far.

Anyway, I'm wondering if you might want to test the benefit of a 90% change by doing it on a small scale first... before you invest in the cost and effort of doing at 200+ gallon change. Is it practical to simulate your setup in a smaller spare tank with 90% fresh mix and a few of your (dipped) corals just to see if it makes a difference?

03-31-2011, 2:15 PM
This past weekend I did a full out 100% water change and did away with the sand. I'm currently seeing some diatoms starting to develop but as of right now, that's the only thing I have noticed. Hopefully I have no further issues. I'm interested in this so I am tagging along. Wishing you the best!

03-31-2011, 3:44 PM
Wow... I was on board with the water change to maybe help the "mystery problem", but it you are having an aiptasia outbreak, maybe it is Nuke Time after all... If I can help, I'm in. I have a spare tank (45 "low breeder"... 48x16x12 I think, drilled) that you can borrow if you need to.

04-15-2011, 11:43 PM
Well, I finally went through with this tonight after the storms passed through. Only took about 3 hours.

I had made up around 280gallons (the most I could fit in the containers I had). A couple of quick estimates in my head, and I figured I'd need around 200 for the DT, 70 for the sump, and 15 for the skimmer.

I started by turning off the appropriate valves to Christine's 300g tank, and then turned off the main pumps, and turned on my waste water pump to start getting the water out to the sewer. I drained my skimmer and Ca reactor, and then went upstairs with a Mag 9 and a hose, and drained my DT by simply pumping water into the overflow.

The only real issue I ran into was that I heard a splashing sound when I got a little below halfway in the DT. I finally saw one of my Hawaiian flame wrasses with my flashlight, who had already lodged himself into the rocks for the night. I assumed the wrasses would have gone into the sand, but I guess not. I flipped the main pumps back on long enough to refill so that he was underwater, and then used a wooden chopstick to coax him out. 5 mins later, the draining continued.

I took the DT down to about 6" (the tank itself is 26" tall) - all my fish were still in there and were starting to get visibly stressed, so I stopped.

I headed downstairs, and added water from my three containers into my 200g sump, and let things mix and run through the skimmer until it was mostly full, then turned on the main pumps again for everything to fill up.

In the end, I had about 3 gallons extra; it was remarkable how close everything was. I'd estimate that I had ~30g left in the DT and ~10g left in the sump that didn't get changed out, so figure 40g left out of 320g total, so I did around an 87% water change.

I didn't get the parameters perfect. The water was a little warm (80.5 compared to the 78.5 going out), and I overshot the salinity, due to having to mix up and store the majority in an open top frag tank, so evap raised the salinity over the past week. I ended up at ~1.029, and started at 1.026. This is more of a change than I wanted, but, I was there and had the time, and figured the corals were already stressed.

My skimmer is doing it's thing and I replaced all my carbon - 1 gallon of new carbon in a 6"x20" FMC, and finally, put in fresh felt filter socks.

At this point, only time will tell. I'll post a couple pictures tomorrow.

04-15-2011, 11:51 PM
Glad everything went so smothly. I hope this takes care of your problems. Three hours isn't too bad either, I spent more time than that tonight rearanging my corals!

04-15-2011, 11:57 PM
wow. I hope all goes well....let us know

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05-16-2011, 3:14 PM
update ?

05-16-2011, 4:10 PM
update ?

I was wondering the same thing on Thursday while driving...