Re: soil substrate OR gravel and laterite?

[jacques gerber <s21340952 at tuks_co.za>]

Hello Rich:

I certainly would not use potting soil if it's anything like the potting
soil you get here in South Africa - lots of organic material that will
certainly rot down and make a disgusting mess.

I use a heavy clay topsoil from my hometown - it varies from 50 to 80%
clay. It has little organic matter and has never been fertilised. I mix
this half and half with wet vermiculite and then add 10% by volume
acidic peat. I put this down in a thick layer, usually 1 1/2 to 2
inches, and cover with fine gravel - maybe 2/3 inch or so deep. I like
fine gravel - 1-2 mm or so. Suspect its a little too fine though.

None of my tanks have lasted more than a year due to moving and
suchlike, but they did show continuous and fast growth with no
deficiencies during that period. All had 20 watts/foot daylight spectrum
light and CO2 injection (the old sugar and yeast type. I redid the tank
I set up about a year ago three weeks ago. We had painters in the house
and one dropped a paintbrush in the tank - what a mess! This tank was
done with a red subsoil found here in Pretoria where I now live - Growth
was not as good. I've redone it with soil ship 1000km from my hometown.

Pulling up plants can be a nightmare though. Bits all over the place.
You have to be really sure about what you want. 

Jacques