So I bought this canister filter second hand at my LFS for $30. It has the ceramic rings in one of the trays and have 2 empty trays with one of those having an optional sub tray splitting it in half. I'm currently breeding eureka red cichlids and upgrading them to a 55g from a 29g tall. What medias should I use in the empty trays?!? Thinking using crushed coral in one of them to help raise my ph from 7.6 to closer to 8.2. Possibly using some Texas holey rock for decorating to help this as well. Here are some pics of what I have.
