All my sponge filters are the dense foam. Pieces of food stick to the outside, and during WCs I shake or twirl the sponge filters underwater and the stuff gets picked up by the hose.
I guess that was my reason behind wanting to ditch them - BUT as phil reminded me they are great for backup if there is a power outage...I do have a battery powered air pump hooked up I connected with a relay to auto turn on if I lose power,:P
I did remove one of the two, and moved it to where crap doesnt land on it and that has improved things... I was thinking out loud I guess