Soil substrate

[phishluvr]

Is there a point where you could have too deep soil in a planted aquarium? I have 3-4" soil topped with 2" small rock. At what soil depth, if any, could cause an excess of anaerobic bacteria to build up in pockets and create an toxic amount of gasses, like methane that would hurt my fish?

 

[phishluvr]

ps. this is a low-tech tank. 75 g, 1 watts/gal, fluval 304, no CO2, temp at 80.

 

[opiesilver]

What kind of soil is it? What color was it when you first put it in your tank?

If the soil contains organic matter then it's going to produce methane gas as well as a few others too. It's just normal the normal break down of soil, no matter how much or how little you use. The best way to combat the gas build up is to aerate the water with a bubble stone and air pump or a HOB filter.

 

[Silly me]

The best way to combat the gas build up is to aerate the water with a bubble stone and air pump or a HOB filter.

I think phishluvr was asking about the dead spots cause by dense sand in a planted tank, as it never gets vacuumed..

these do cause problems and if you see bubbles when something disturbed the gravel, you might need to look into it..

personally I found that MTS is the only snail that could help you, but once the dead spots started, they will not burrow into it.. they are more of a prevention than a cure.

 

[phishluvr]

It's set up per Diane Walstad's book on low-tech planted aquariums, so the soil is the store-bought garden soil.. It is sending up bubbles, and it has had the hardest time cycling this last move. After 6 months, the bacteria bed in the fluval is not established and my tank stats are those of a 3 week old tank. ??? The lfs is baffled as to why its not cycled yet. Perhaps the gas(es) are inhibiting bacteria? I also wondered if my fluval 304 isn't quite heft enough for the job.

I've never had this problem in the 15 years I've maintained tanks, but I'm new to planted tanks, so it's frustrating. I'm ready to tear it down and buy some oscars with a bunch of misamo balls for them to roll around.

 

[Nospherith]

 

[Nospherith]

the soil is the store-bought garden soil.. It is sending up bubbles, and it has had the hardest time cycling this last move.

hmm... it's sketchy using that garden soil. I guess if you got it out of a bag then its ok but adding ordinary topsoil with all the protozoans, fungi, spores, parasites, and just other bacteria living in it would make an aquarium rather... dirty.

Topsoil or garden soil sold in nurseries or retail gardening centers commonly has high proportions of compost or manure added which make it unsuitable.

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However, it doesn't seem as if the bacteria is as much as a problem as the amount of organic material in the soil.

 

[opiesilver]

Don't be too quick to tear down that tank.

A common thing I've seen in the last 20 years with heavily planted tanks is that your normal cycling process will never complete in the classical way. Your plants will actually out compete the bacteria for the foods these bacteria need. They will directly use the ammonia that you fish will create.

The decaying organic material and the bacteria breaking it down are going to produce sulfurous compounds which heavy root feeding plants do really like. Not all the gases are necessarily bad.

What I would like to know is what are your current water parameters? How heavily planted is this tank? Let's see if you really need to be worried yet.

 

[Nospherith]

Garden soil, depending upon how much it has been enriched with compost, probably contains from 1% to 10% organic materials and is an excellent source of humus. It is moderately fertile and has a moderate oxygen demand upon initial submergence. Garden soils which grow vegetables well probably have a good balance of essential mineral nutrients and are a good choice for use with aquarium plants.

From Substrates for Aquarium Plants

Yes, there is no need to dismantle the tank. Cryptocorynes, Echinodorus, and various other root feeders will really like the labile soil. But it is labile, in that it is chemically unstable and water parameters should be monitered carefully until things settle down. Anyway, it's better for plants than just plain gravel.