I recently just switched from HOB filters to a sponge filter designed for my tank size (20 gallons). The one I am currently using was recommended to me by my LFS. It is a Chinese brand and I honestly cannot remember the name of it. As far as biological filtration, it is great. But for mechanical filtration, it is less to be desired. The suction is so gentle that even the smallest of waste particles don't suck up at times. My tank after only a few days after a water change has tons of white particles resting on the ground and in the water column. I have four full grown platies so waste is a huuuuge issue. Is there a brand of sponge filter that you use that is great with mechanical filtration?? Or should I possibly up my sponge to one that is designed for larger tanks?? I am aware that sponge filters are not necessarily designed to be super effective with mech filtration as power filters are, but I really love using a sponge filter. Thanks in advance!