Hi Everyone, Need your help! I have a 35 gallon tank with an Aquaclear 50 filter, I would like to use a cannister filter on this tank. What is the safest way to change filters without losing anmy fish. In this tank I have 2 gouramis, some neon tetras and a few rasboras. I tried adding the sponge and the bio portion of the filter when I did this change with my 35 gallon cichlid tank and lost most of my fish...any suggestions?