Why do fish just die?

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Substitute "biological activity" for "plants" and it all means the same. pH is highest just before the lights go off and lowest shortly after they come on.

I'll have to agree with the pH aspect. 7.2 is really low, even for a reading taken just after the lights have come on. Granted... pH buffers only afford a temporary increase in pH, but that doesn't mean that a low pH is unfixable, and should just be accepted.

I've got an article bookmarked at home about low ph causes/solutions and I'll post a link later unless someone beats me to it.

I won't get into the debate of whether nitrites are harmful or not, but I will say that in a properly cycled tank with a bacterial population large enough to support your bioload, you shouldn't see ANY nitrites show up.
 
Could it be that I'm using RO water from Lake Michigan? I know it doesn't have much much dissolved limestone like well water in this area would.

I read an article at reefkeeping and I think I'll try aeration as a first step to see what the results are.

Rich
 
RO water is more or less pure, regardless of where it came from. Doubt that's your problem.

That'd be the easiest thing to do first... open up any glass tops if you have them and point a couple powerheads at the surface to get a good ripple going.
 
So if it's respiration which lowers PH then .....

Cause there does not seem to be anything in there that needs photosynthesis, right? I get the concept and the chemistry just not the application to this FOWLR tank. Something is low somewhere, alk, lids, bad environment. I just don't but the PH goes down at night just because it does. If it goes up during the day because of Photo and there's no photo-'plants' then it stands to reason.

Anyway.. either way. I would stil think the PH difference between the probable LFS PH and your tank would be troublesome..
 
Yeah... that's the linky. I knew someone would find it before me!

The pH shift, in my experience, is only like 0.2 or so. Enough to see a shift in colors in the test tube, but not enough to really know exactly what the number is.

Even in a FOWLR tank, there's still algae. Seems like that'd be your photosynthesis link.

But I agree... a pH reading of 7.2 is well below any normal daily swing - unless you're starting out at 7.5 or something like that!
 
The 7.2 is the reading I get all the time. I've never checked with the lights off. I always check around the same time on Sunday morning when I do other maintenance. I do keep a log of when I've taken readings and write them down, so I can look back and see it's consistant.

Also isn't the water falling into the sump causing enough aeration? Seems like it makes a lot of air bubbles when falling into the sump?


What could the other causes be or what else can I do to get this to a healthier level?

Rich
 
Yes I read it a couple of times, trying to decipher what course of action to take. Looks like I haven't been changing water enough as that's what resupplies the trace elements. So I'm going to do that and then add an airstone to the sump and turn the fans more toward the surface to get the PH better. Then just keep up with it.

Am I the only one that has this problem? How did you correct it if you've had the problem?

TIA, Rich
 
pH would be the contributing factor and perhaps I missed it, but I did not see where that number was listed by the OP? Anyways, what is the salt mix pH stabilizing at?
 
weird thing is that they lived for weeks, not days or hours, in the 7.2 (assuming the test kit is correct and not knowing what the alk is).

A=0
B=.5
C=10
D=7.2
E=1.022 Refractometer
F=90 gallon with 20 gallon sump with protein skimmer
G= 4+ months old.
 
Wow, not sure how I missed seeing that one, thanks Capt :) Depending on the source water, if within normal parameters of 7.8-8.0, the constant exposure of such a low pH would inhibit respiratory functions and accelerate secondary infections. I'm sure each animal has its variable limits, but eventually time breaks down the system. That would be my guess and as for the pH being that low I would conduct some tests on the salt as well to make sure it isn't a bad batch...just some thoughts.
 
last i checked.. crushed coral is a great ph booster.. my ph is at 8.2 every day.. i use ro water which has 0 ph in it lol.. it shows like 5.8-6 when i tested it. but it as soon as it hits the water takes on the ph of 8.2. my live sand has a bit of crushed coral in it.. maybe you could try that?
 
Crushed coral, same as aragonite, will only boost pH when it drops to about 7.6ish, perhaps lower. All manufactured salts buffer the pH to at least 7.8 and even if there is a buffering effect within a dsb layer it will precipitate out and provide very little, if any, impact on the system as a whole.
 
... I would conduct some tests on the salt as well to make sure it isn't a bad batch...just some thoughts.

Good point. Test up a batch of water that's been aerating for 24 hours or so. I've heard recent rumors on another board about some buckets of IO mixing up with low pH. Seems like there's always rumors about bad batches of salt floating around there!
 
Maybe the fish had something wrong with it all along. Liver or heart who knows.
 
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