I use filter floss in my plexiglas canister. It has a filter sponge at one end and the filter floss at the other end where it opens for carbon change out. I bought that one a long time ago. I have an old Eheim unit that someone gave me that I need to dig out and use so that I can run both carbon and phosphate absorber. I have mixed the two in my canister in the past. Currently I'm running carbon in the canister and phosphate absorber in a sock.

Gary