New substrate

[tungsram]

Is this an acceptable substrate for a planted fish tank?

1/2" Vermiculite
1" Sphagnum moss
2" Garden soil

I'm looking for a better substrate and I really don't want to dump money nito Flourite or the other name brands.

[Damon]

Its a good substrate but soil isn't something to be used lightly. Many things can go wrong with it. If you don't want to spend a lot, just use laterite and soil combined. Less than 30 dollars will work in a 55 gallon tank.

[MyraVan]

Why would soil + Laterite be better than plain soil?

I have a tank with a soil bottom (1" soil + 1" gravel) and it grows plants really well, but it turns the water yellow. Not all that nice looking. I think for the next tank I'll use proper aquatic soil rather than random garden soil, in hopes that it won't turn my water funny colors.

[Damon]

Laterite contains iron among the others micros plants need. Laterite also absorbs ferts and slowly releases them back into the water column.

[MyraVan]

As far as I know, from reading Diana Walstad's book, soil also absorbs and then re-releases fertilizers. I also seem to recall that she also felt that plain soil provided enough iron on its own, but I'm much fuzzier on that one... One thing she does mention is that if your soil is acidiic (too much peat in it) and you combine it with a high-iron additive (like Onyx sand, possible also something like Laterite) then the iron is released all at once and you can get problems with iron toxicity. Or something to that effect. Still, you never know how it will work until you try it. Diana suggests experimenting with small tanks so you get the feeling of what works for you, and that advice seems good to me.

I must say that, ecologically, my plain soil + gravel tank is a big success. All the animals + the dozens of white cloud mountain minnow fry are doing fine. But it doesn't look good at all. The water is quite a dark yellow. I have to change a fair amount every week to try to keep it from getting too dark, as the humic acids continue to be formed from the decomposition of the organic stuff in the soil. (So maybe laterite would help with this problem, as it's just plain clay, with no organic material in it.) I missed my water change last week since I discovered the fry, and read that you should wait until the fry have been free-swimming for at least a week before you change any water. Also, there's a fair bit of algae, and even some floating yukky stuff on top. Normally I would get rid of it by scooping it up with the water during a water change, but I suspect it may be helping the fry to live -- it's probably providing food and a home for some tiny critters that the fry would eat. So, at least for now, I'm going to leave the rather unattractive algae in place. At least, most of it....

So I have to agree with Simpte that soil isn't something to be used lightly. It does have some disadvantages. In a few months I'll be able to tell you how commerical aquatic soil + gravel works as a substrate...

[atltk]

I have a soil substrate (thin layer of clay, a layer of 5 parts potting soil to 1 part peat moss, and gravel). My plants do great in it, and especially thrive when I have my CO2 system hooked up. Water cloudiness CAN be a problem initially, but not if your careful when filling your tank. I put a large dinner plate on the gravel and slowly pour the water onto it, this really helps to not disturb the soil.