Filter biological media substrate suggestions?

[brich999]

I use laundry bags since they are cheap and don't impede flow, but you can remove your media and give it a rinse in tank water when cleaning. For compare, my Lfs ordered me a 5.3g 20l bucket of pond matrix for 95 bucks. Now I know that's enough to fill a lot of big canisters, but hey the stuff is pretty cheap compared to name brand ceramics