Re: problems with the "Kelly substrate"

> From: Elaine Lachance <carrief at odyssee_net>
> I am en enthusiastic newbie who set up a 20 gal tank in
> august using the bassin soil and vermiculite (2") over
> 1.5" of 1/8" gravel. The tank is lighted with 2 24" 
> fluorescent tubes. Plants include hygro polys., hygro diff.,
> rotala macandra, elodea and anubia nana. Fish pop: 4 black
> neons, 1 ram, 2 rummy nose and 4 blue-tailed corys. I use an
> Fluval 203, and a Powerhead 201 for injecting CO2 with the
> DIY yeast method posted on the net. I regularly add Pond Tab
> and chelated iron. Everything seemed to be doing just great
> until a month ago. I was replanting cuttings from a hygro.
> Large bubbles came up, and I noticed that the stems of a few
> hygros had rotted. The fish and plants looked ok, amonia and
> nitrite registered zero, so I didn't worry about it. Three
> weeks ago, nitrates went up to .2 ppm. Several water changes
> were enough to bring them down. A week later, I added 4
> rummy noses. They all died. Also, I added two new plants, red
> ludwigia and cardamine. Both became mushy in a week. One more
> rummy nose died, and 3 other corys died also. Nitrite and 
> amonia still register zero. I read in different postings
> that soil could become anaerobic - could this be the case?
> I find it odd, though, because the soil I bought is supposed
> to be made especially for aquatic gardens. I'm really at 
> loss here.

Presume you mean soil/vermiculite in the bottom layer covered
by 1.5 inches of gravel? Regularly adding Pond Tabs is not a
good idea. What you should have done is break up one or two
of the tablets and distribute them on the bottom of the aquarium
before adding the soil/vermiculite layer. If you are just putting
them in the water, then that will explain problems with nitrates,
phosphates and possibly H2S if there isn't enough Fe present
in the substrate to handle the amount of sulfer there. Sounds
like there is too much fertilizer. When I've had problems with
certain sensitive plants melting the stems, the problem seems
to be cured by increasing the amount and frequency of water
changes. I'd suggest you do that (if you haven't already) and
don't add any more fish until you get the plants and fertilizer
working properly. Are you testing Fe concentration? or using
a commercial mix at the recommended dosage? Some brands like
Tetra of Ferreal are a waste of time. The three brands I have
used or know are adequate are: Dupla, Tropica Master Grow and
Flourish. I expect PMDD would be similar. Also, how stable
is your pH? Wild fluctuations could also create problems for
your fish. It is also very possible that you have a certain
amount of H2S and depending upon the amount of fertilizer tablets
in the substrate, it might worsen. Any idea how much is in