i have a whisper 30 gallon power filter for my 29 gallon tank. and i also have a 40 gallon sponge filter. the sponge filter is working harder then the power filter and i have to clean the whole sponge out every week. I AM GETTING A ODER SMELL IN MY TANK AND I PUT EXTRA CARBON IN IT AND EVERYTHING AND I STILL HAVE THE SMELL. I need to find a better power filter for my tank so whats ur guyes ideas. should i get a 40 gallon filter or what. i am looking for something cheap and the filters dont cost that much.