Hi All, I have Fluval filter. It seems to slowly loose power over a few weeks then completely stop after about a month. I then give it a little clean and it works again. Recently I bought a new sponge for the middle and this improved the filters greatly. However i am noticing it after about 2 weeks it is starting to slow again. My question is, is this normal? And should I be cleaning/replacing the sponge inside the filter. My thinking was that this shouldn’t be changed or cleaned to often as it would disrupt the tanks biological environment? Any help would be appreciated.