CUP-311 Replacement Pond Filter Foam

I’ve been using this replacement foam for two weeks now, and my pond’s water is noticeably clearer than with the old flattened block. The sponge bounces right back after each squeeze, which tells me it’s trapping debris properly again.

The foam density is perfect—my old block had lost its shape, but this one immediately filtered the sludge into a clean, crisp pond. It’s holding up well through the first week of heavy fish waste, and I can already see the water clearing faster.

My old foam had gone so flat it was basically just letting everything through, so I swapped in this one and the water clarity changed within a day. The fact that it springs back after a squeeze tells me the bacteria colony has proper structure to cling to again.