I set up a number of soil based tanks for some folks, as well as myself for a number of years.

I've suggested things such as a good soak 2-3 weeks prior to use to leach out the NH4. Or alternatively, boiling for 10 minutes or so.

One thing that came up was something I've not seen others mention and many had been using the straight 100% soil on the bottom layer, generally about 1" deep. This works also.

But I never really liked that. My uncle owns a Green house in GA and suggested when I was kid to mix the soil with sand at 50-75% sand for each part soil to reduce the richness and when you uproot, it makes far less mess.

So I've pretty much stuck with it since.

The method is simple and gets around many of the issues that folks have with soil.

1.Soil is well, dirt cheap.
2. Rich in all the nutrient goodies
3. Available everywhere
4. Sand is cheap as a sediment gets as well, but lacks the nutrients

Mixing these two works very well.

So, I simply mix 1 part soil to 2-3 parts sand=> wet> then mix good.
You want nice dark sand, not "mud".
Then you add about 2-3" of this and maybe a cap of 1" plain sand.

You can add 3-4 parts sand and use it without any cap actually and then lightly vacuum the top to remove any leftover soil.

While this is not as rich as the pure soil, it also does not reduce the sediment nearly as much, and it's still a lot of soil, just spread out a lot more in 2-3" vs 1".

You can add the "mud cubes" later as the plants get growing well and remove most of the nutrients. Siol + water = mud. Add mud to ice cube trays: freeze. add mud cubes to the plant roots.

You may add anything you want to the soil also, root hormones, KNO3, CaCO3 ,more peat etc.

The results and usefulness are when you replant and the sediment does not get nearly as stinky and reduced, the sand provides better flow and less mess, better able to hold the plant roots down etc.

As far as having less nutrients than a pure soil layer, well think about it.........
the total amount is still relatively the same, but instead of a muddy mess, you have it spread interspersed with the sand.

Also, but the time it does run out of fertilizer, the tank's cycling is producing it's own waste to supply the roots/leaves etc.

You can then use the mud cubes etc, or switch KNO3/KH2PO4/Traces at small dosings to accommodate sustained growth.

I think it's pretty easy and folks should try this cheap method out.
It's been around a long long time and works well. Do many water changes for the first 2-4 weeks of a set up if you use CO2 or Excel.

I think this routine will resolve most if not all the issues some folks have with soil.

Regards,
Tom Barr
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Is this method good for higher light tanks, or just the low light ones? For example, how about a 2 watt per gallon tank? And, do you not dose NPK and traces at all in the beginning?

That was cool. Intuitively, after years of experience with soil underneath gravel, I think that would work much better than one would think at first glance.

I've noticed that when the soil have aged a bit it settles *very* quickly when uprooting thus not making any cloudiness at all - just a bit of mulm around the area where you uprooted the plants. If mixing alot of sand and just a bit of soil thoroughly it should be a bit like getting a well mulm-infused bottom/substrate in seconds.

I will try this next time I setup a tank.

When you use the term "sand", are you referring to the very fine playbox-type material or something coarser? If the former, wouldn't an inch of it over the soil-sand substrate restrict the flow of nutrients from the water column to the substrate?

I use 1.0 to 1.5 inches of 2-3 mm gravel over soaked topsoil, and I have never had a problem with the soil getting into the water column. Of course, I don't do a lot of uprooting of established plants. Some, though.

If a small amounts of soil should get into the water column, it is readily removed by the filter.

Bill

I've used both 1 mm sand and 2-3 mm sand which I prefer personally.

Well mixed, the 2-3 mm sand works quite well for the bottom 3" nutrient rich layer.
then 1" or so of the 2-3mm on top of that.

These tanks work very well for high light tanks BTW, 4 watt gallon etc.

Regards,
Tom Barr

The next time I do a major overhaul of my tank I will try this. But, I'm still wondering, should I do routine EI fertilizing, and just depend on the substrate to augment the fertilizing, or should I wait to start EI fertillizing until the substrate seems to be running out of nutrients? Or neither?

I like the idea of having a heavier substrate to make it easier to plant and keep plants from floating back out. Plus, this might make substrate formed into hills and valleys last longer before they self level.

I have a question about EI and low light, non-CO2 tanks. Specifically, should you attempt it?

Since EI needs water changes with each dosing, and since that kind of tank shouldn't have frequent water changes, it seems to me that EI wouldn't work. But then, I've been wrong before. That's why I'm here.

Bill

My tank gets a continuous water change, a trickle of incoming tap water with an overflow dumping the excess tank water out doors. If this were a low light, non-CO2 tank it should do fine, since the incoming water/CO2 would be a constant, not a periodic change. Right now I use only 72 watts for 45 gallons, so I am approaching low light, but I still use EI and CO2. A soil substrate should work well in this type of tank, I would think.

That seems logical, since the environment of tank is stable.

I think the problem comes about when new water is introduced to a "low energy" tank, perhaps with more nutrients. But I havn't checked that myself.

Bill

You should not use EI on a non CO2 tank, you can use the just enough method instead, a little bit and eye ball at the lower end rather than adding a lot.

Since demand and uptake are low, you have plenty of response time.

Regards,
tom Barr