green water and fish loss

KateA.

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Apr 7, 2003
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we have a mess in our retail marine system and we are getting conflicting opinions on how to fix it. I'll skip all that and tell you water test results: ammonia- .1 ; nitrite- .1; nitrate- 110; calcium- 280; ph- 8-8.5; gh- 500+ (can't remember if this is important in marine?); kh- 70; phosphate- .25; Salinity 1.021-22. Things turn green overnight and we do overfeed. With so many hands doing it, I think I've told folks to lay off, then I see them doing it again. We have fish for a couple weeks, everyone seems to be eating great, good color, then they stop eating, fade and die. I've tested copper and there's none. It's got 2 huge bio wheels and a U.V. Sterilizer and it's fish only-crushed coral substrate. We use 100% RO and test it periodically to be sure. We are stumped. Once this chemistry stuff gets to a certain point my brain shuts down and fails to comprehend further, but give me some thoughts and opinions.
 
Wow, sounds way off.
If the ammonia and nitrite are really 0.1, then something has killed part of your biological filter, they should be 0. This could very well be why your fish are dying.

Nitrate at 110 ppm is way high, combined with the 0.25 PO4, I would expect a substantial growth of algae. I wouldn't expect that to kill the fish, though.

A few things you haven't mentioned:
1. The age of the system.
2. The frequency of partial water changes, and gravel vacuuming. Based on the low Ca and high NO3, maybe not often enough.
3. How rapidly do you go from 0 fish to a full load. An idle biological filter may not be able to

Is it possible that you are going from an empty system to a full fish load too fast? The biological filtration may not be able to keep up.
 
Great points raised

Yes, the nitrates are not at a level to kill fish, but they are at a level to suggest other things are "not right" with the system.

I'm curious as to the oxygenation of the whole setup. I'm not sure about the surface exchange (I know you have two huge biowheels), but there can't be anything wrong with a good surface agitation, as well. Is that present? Water circulation in the tank as well as a good gas exchange at the surface just can't be beat to maintain goo oxygenation, IMO.
 
Originally posted by mogurnda
Wow, sounds way off.
If the ammonia and nitrite are really 0.1, then something has killed part of your biological filter, they should be 0. This could very well be why your fish are dying.

I need to make them keep better records. I've tested before and it's been zero, but I keep catching them over feeding and we just restocked a few days ago.

Nitrate at 110 ppm is way high, combined with the 0.25 PO4, I would expect a substantial growth of algae. I wouldn't expect that to kill the fish, though.

that overfeeding thing I'm sure.

A few things you haven't mentioned:
1. The age of the system.

up and going for 2 years

2. The frequency of partial water changes, and gravel vacuuming. Based on the low Ca and high NO3, maybe not often enough.

I'm sure of that- probably only every other week on water changes and gravel siphon once a month probably


3. How rapidly do you go from 0 fish to a full load. An idle biological filter may not be able to

never 0 to full, a few, like 1 per tank to 2-3 per tank

Is it possible that you are going from an empty system to a full fish load too fast? The biological filtration may not be able to keep up.
 
Re: Great points raised

Originally posted by FISH WHISPERER
Yes, the nitrates are not at a level to kill fish, but they are at a level to suggest other things are "not right" with the system.

I'm curious as to the oxygenation of the whole setup. I'm not sure about the surface exchange (I know you have two huge biowheels), but there can't be anything wrong with a good surface agitation, as well. Is that present? Water circulation in the tank as well as a good gas exchange at the surface just can't be beat to maintain goo oxygenation, IMO.

I've wondered about the surface oxygenation. It doesn't circulate good enough, to me, but there's not much I can do with it. We point the returns up to the surface and it ripples, but it could be better. I will test that next, if we have a kit.

So, we'll start with more gravel siphon water changes, reduce feeding and see what happens in a week. Any other thoughts?
 
No harm in.....

More circulation, better aeration.

When you said "retail system" I'm assuming it's not a nano tank. ;) These large systems can so often be underoxygenated. Part of oxygenation is water turn. For example, you could have a blasting fountain on a lake, but if not all the water is getting there, it's inefficient.


Here's the problem with a lot of retail systems as I've observed them. If a "mondo" pump is put in there for circulation, store owners are too often faced with fish "stuck" to the intakes. This is understandable. To make matters worse, many retail systems are not set up optimally in the least sense! :eek: The idea is to "turn" fish, so there's not much given to a "biological" filtration system set in place. There is crushed coral, vacuuming, etc. The usual maintenance. There just isn't the stability in many retail systems that hobbyists have in their own home setups. Yes, it's true. ;) Hobbyists no doubt have much healthier, less morbid systems. ;)

In the absense of a really strong water flow, and surface exchange, there must be alternatives in place - and it is very doable. Now, most retail SW setups do not enlist the usage of "bubble curtains," as this is squeamishly a "freshie" thing to do. ;) But it does help with aeration from the depths of the tank on up. Understandably, O2 exchanges by mere "contact" of all the molecular activity going on, but the question is, is it enough? In larger systems it can indeed be a problem.

In one large non-sump system, we used two hang-on type filters with extended "draw siphons" which took the water from about 3/4 down in the tank, and served only to "splash" it back in at the surface. This circulation is better than an inadequate powerhead, and you can have fairly large "heads" on the intakes which help prevent the "sticking" of fish. :eek:

It sounds like your system obviously is completely O2-deprived, but I'm willing to bet you could use some help in that area. I could be off-base, but this is so often overlooked. One thing that can be done is to actually generate circulation/aeration manually. This can be done as little as once a day in a retail environment and provide great benefit. It's simple as pie, too! :) I wouldn't recommend getting a yardstick and flailing it about as though you were concocting a witch's brew, but if you folks have a good airpump you can blast some fresh air in via a hose for a few minutes. You can move it about the tank, and this will only add insurance that you are getting that water circulated.

Some of the best circulation comes from active fish! And I'm sure you have plenty in there, so that's why I somewhat question the circulation as being too inadequate. I just think, however, that it is never a bad idea to add extra insurance. "Fresh" tanks always seem a bit "healthier," don't they? ;)

How is the actual air source near the tank? If you are drawing upon stank air, you're not going to be exposing the tank to fresh O2. I've been in some really "closed up" stores, and you can tell just from the "mustiness" that it's not "fresh." I'm no chemist, but I can't see that as being more optimal than fresh air.

There could be a combination of things at work, and that is the case more than a few times with hobbyists, as well. We have problems, so we are looking for a "solution." The key is we have problemS and so we should be looking for solutions. A bit of a play on words, but I believe there's some truth to it. If more than one thing is at work against us, we may need a combination of "fixes."

Starting with optimal circulation and a fresh O2 exchange is the elimination of one potential problem that can wreak havoc on tanks, and often it's not seen until "long term." Conversely, some folks can whack out a huge water change, and the fresh water contains such an imbalance of oxygen that the fish actually die within 12 hours. This can be seen by a sudden "panting" of the fish, or "gilling." We are wondering what the heck can be "wrong" especially since we just did a "good" think for our tank. Ah, but this hobby is not about "sudden changes," even for the better. So as you tweak in that system, try to do so gradually. Dumping a huge amount of water in order to get "fresh" water in could prove fatal if you're already dealing with a depleted system. Agitating it, and getting fresh O2 via the surface exchange is far more gradual, and less "invasive."

There's a lot that might be at work here, and this is just one aspect of concern - certainly in no way a "diagnosis." But maybe you'll get some suggestions that might answer your problem from the folks here! :)
 
One other thought. Cynanide-caught fish often look quite good until organ system failure. How much do you trust your wholesalers? It's especially a problem with fish from the Philippines.
 
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