Planted Tank Guru
Join Date: Dec 2002
Location: Portland Orygun
First question is why? Just go with Flourite and gravel.
Second see my Guide. The section on substrate. CPA (cat piss absorbent) in the same bag can be two totally different products in different parts of the country. Most of it breaks down into a nasty mush when submerged in water.
Just use either straight Flourite or Flourite mixed 50/50 based on depth (not weight). Use a gravel that is the same grain size as the Flourite or you will end up with the larger stuff on top. Put down a layer of peat moss on the bottom and you will be good to go.