pockets anaerobic gas are no myth....unfortunately

Well that leaves us in a pickle. No sulfurous egg odor and no large scale pH swing. Any other ideas?

I've been poking my nose in and out of Diane Walstad's book for its section on exactly this stuff. I'm more confused then ever :confused: :eek: . I think I really need to sit down with a chemistry book at some point. :rolleyes:

Gregga, sorry about your fish :(
 
Originally posted by gregga

For what it is worth, the substrate in question was crushed coral.
Click to expand...

HUGE arguement against any ph swings but down, unless your water change was with liquid rock. the substrate in question kills the "old tank syndrome" theory also, the natural buffering capacity of the crushed coral substrate would prevent the formation of NH4 (ammonium), or at least keeping it from being concentrated. at the ph the crushed coral would create it should all be NH3 (ammonia)... it sort of rules out the massive release of ammonia theory. with the substrate in question, you should have a fairly stable but high ph.

a "normal" sand or gravel substrate might lend credence to the theory, but not crushed coral. the same principles just don't apply.

sorry for ressurecting this, but i followed it from another thread.

edit: i tend to lean towards rtr's theory, or maybe something like an overwhelming release of bacteria.......
 
Last edited:
Please do not apologize for resurrecting one of the more interesting threads this forum has seen. I for one am glad to see it again because I never came to a conclusion as to why the fish died.

RTR rebuffed Wetman's chemical reaction explanation but never to my simple brain explained the cause of death. Maybe it was lost in the chemistry - I am not sure.

Either way, can someone, anyone, tell me in plain terms why the fish died so rapidly?

Then, also in plain terms, tell us what precautions those of us with fully planted tanks should take? RTR's Old Tank Syndrome article mentions removing all but Crinum roots and replanting from time to time to get old dead root structures out of the tank. Is that it?


I apologize for harping on this whole thing but this kind of full tank disaster is what keeps me awake at nights. If an aquarist of Gregga's experience level can lose it all in 30 seconds, I want to understand why and how to prevent it from happening to me. Thanks to all who contribute.
 
Tom?StL - there is a newer thread on DSB in Freshwater that picked up and ref'd this thread repeatedly. I don't have the URL, I believe scott started the thread.

And I don't know what killed the fish. But I do know why it happened - an untended heavily organic substrate (and very likely anoxic) was disturbed suddenly and massively. That is an absolute no-no. If such a situation comes about, remove all the livestock before disturbing, repalace all the water afterward, and run carbon a few days before introducing test fish.
 
Here is an experiment you can find out the content of the gas. Invert a clean transparent plastic cup over the substrate and disturb it until enough gas is collected at the top. Get a syringe and punch the plastic to collect the gas. Prepare a test tube with distilled water and bubble the collected gas through the test tube water. Use your nose to smell anything unusual while you are bubbling the gas such as rotten egg or ammonia smell. Check the test tube water later for ammonia and pH. I don't know of any sulfide test kit readily available but your nose may be the best tester.

I don't keep plants and all my tank substrates are kept to less than 1/2 inch. When I do water change, I vacuum the substrate wall to wall and also disturb it to disperse the dust. Despite regular cleaning and thin layer, I still observe bubbles from underneath rock and where the fish piled up the thickness. I suspect that the gas is mosly nitrogen and methane as the two are insoluble. The toxic gas like H2S and ammonia are highly soluble and I don't suspect they can be present in my substrate with the way I managed them.
 
Tiger, my amateurish reading tells me that you're right about methane not being readily soluble, but that you're not right about nitrogen.
At a University of Idaho website I googled-- www.chem.uidaho.edu/~honors/airsol.html -- I read: "oxygen is almost twice as soluble as nitrogen, but since there is four times as much nitrogen in the air as there is oxygen, we'd expect to see twice the molarity of nitrogen in water as there is oxygen."
 
Well reading this thread has got the synapses afiring and the brain cells aworking and from the depths of my memory came an idea about toxic lakes in Scandinavia (funny how fishkeeping makes the most obscure things highly interesting)

I can't help thinking that the main thing that would kill all the fish in the tank so quickly is co2 sooooo.....

I did a search on google and guess what??? There's information which I think will shed light on the matter, even involving the coarse coral gravel substrate - in fact I think its crucial to the info on this site.

Here goes for trying a link

toxic lakes

By the way, is it possible that the pH test wasn't working properly and gave a false recording of pH ???
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom