I have a 180 gal tank with about 40 african cichlids. The tank has been cycled and running great for about 5 months but here is my question. In my wet dry system under the tank the filter pad is very clogged since the water is backing up to get through to the bio balls. If I change the pad it will solve the problem but I will lose my good bacteria. So finally here is my question. What should I do?