Anaerobic spots

[firetank]

eeek anaerobixc spots

while doing a little pruning today, i uncovered what must've been an anaerobic spot in my sand substrate
(black in colour, awful smell??)

the substrate was about an inch in depth; ive done a drastic water change and lowered this depth to about 5mm in 2\3rd of the tank.



i cant get hold of any m.t.s.
but now the sustrate isnt deep enough to plant to...

q:
will the escaping gas have harmed the fish??

ive read a lot about laterite\gravel mixes, do these also generate anaerobic spots if used without a ugf??

any other comments greatly accepted,

thanx

 

[OrionGirl]

Not sure, but I think that the effects are pretty much immediate. If you don't notice fish dropping like flies, you're probably okay. I know TNCGal had the same problem, and with a very shallow sand bad.

Any substrate can develop 'bad' spots. You can do maintenance yourself--stirring up the bottom with a long pole, or get a fish that burrows often (depending on tank mates and bio-load of course). Not sure if it's a possiblity, but MTS are available on Aquabid often--you could try there. Usually pretty cheap.

 

[wetmanNY]

All areas of the substrate below the uppermost half inch or so are increasingly anoxic as you get lower. Lower strata of the substrate are anaerobic. Each layer has its natural bacterial economy.

When organic materials like softened fish flakes and bits of pleco zucchini and dead soft plant leaves are stirred down deep into the substrate, they continue to decompose, but the bacteria doing the job (less eficiently than aerobic decomposers) are naturally anaerobic, either facultative "switch-hitters" or obligate anaerobes that are poisoned by oxygen.

Anaerobic decomposition is smelly, but most of those "swampy" smells are thiols ("mercaptans") rather than the dreaded hydrogen sulfide.

Anaerobic pockets in the gravel are a bugaboo. They wouldn't be there without disturbances during gravel vacuuming. And they'd never come to notice without gravel vacuuming.

It's all turning slowly to good compost, which is dark dark brown like a good soil-- almost "black." It's what used to collect beneficially under UGF plates, unless it was disturbed during gravel vacuuming.

 

[RTR]

I don't often disagree w/wetman, but on this one I do - strongly. I have seen entirely too many threads on the board from folk with Cory whisker problems, sickly apistos (and other small bottom dwellers), continuing up through generalized septicemias and tank wipe-outs from bad anaerobic subtrates. Ask RobertH or cathyh - both are eperienced growers and fishkeepers who have had mysterious problems which turned out to be foul substrate-initiated. If this can get the highly experienced, it is worse for the beginner and intermediate tank keeper. Bad substrate can affect the fish just as can high-nitrate OTS situations.

NIMFT.

 

[rus]

can these areas develop in a wet/dry style sump filter? i do not have a bottom plate under my bio media so it goes all the way down to the bottom of the sump and the sump i am using has no slant in the back corner to keep dead spots from occuring.

 

[firetank]

thanks all for the replies....

I have kuhlie loaches in the tank which i thought would help, but ive not yet seen them REALLY burrow, more shifting the surface...

Im in the UK and cant find m.t.s.anywhere, im not sure if they are even available here....

luckily its been 14 hrs and all survivors.....

anyone think id be better off reverting to gravel\laterite mix??

thanx.

 

[RTR]

Firetank - MTS burrowing is shallow anyway, they do do not dig deeply.