I use 2 pounds of unwashed EW castings under my flourite/peagravel mix (60-40). Works great. Maybe 3.5-4inches in back of tank. The castings were only put on the back half of the bottom pane because i didn't want to have to keep my foreground with more than 2 inches. Fact of the matter is my tank is growing very well now and i would not hesitate to do it again at a later date. |