John innes potting compost..?
Someone has suggested to me that JOHN INNES POTTING COMPOST No.2 makes a good substrate under sand or gravel for a planted tank. This is what it contains [from their own website...]
each cubic metre of mix contains...
0.6kg ground limestone
2.4kg hoof and horn meal
1.2kg potassium sulphate
I don't know if it is obtainable in the States but every garden center in the U.K. carries it.
What are your thoughts on this stuff..?