I feed TetraMin flakes for tropical fish and four sinking cat pellets
once a day about 7pm. Also about every week and a half I feed frozen
blood worms to replace the flake. I do use carbon, Black Diamond
(pakage says phosphate free)..... a very small amount (1 tsp) in one
filter bag replaced monthly.

my aquarium page, info and pics at:
www.geocities.com/spiral_72/Spirals_page.html