Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Kitty litter is often a montmorillonite clay. As such it has high CEC, but has no nutrients until you add them. When you add fertilizers it can hold the fertilizers in a way that plants can get them.
There are other montmorillonite clay products available that look a lot nicer in the aquarium.
The 2 product lines to look into are:
Oil Dry types of materials, of which Safe-T-Sorb is one of the best, available at Tractor Supply,
the greens (golf, ball fields) industry which has several changing materials.
Soil Master Select was a great one for color. No longer available.
Turface used to have some nice colors, but is now somewhat garish.
These products can be purchased at irrigation stores like Ewing, John Deere and others.
I do not like the pale (often white) substrate, either sand or kitty litter. Safe-T-Sorb is a blend of soft browns, tans and greys. Much nicer looking!