hey everyone I've read in random posts of the topic of a big bag that you can get at your local fish store of sponge material that would typically go on the top of the canister filter.....the one that you hardly throw away cause it holds all the bacteria goodness. I asked my fish store guy if he sells the that bulk in a big bag...instead of buying the pads made for the filter....like mine I have the eheim classic. He said yea for around $30. I thought it was super cheap?? What do you all use as your sponge filtration that you can put in your filter...rather it be canister or HOB or whatever. Thanks!