I have a 55 gallon freshwater tank....I have 7 small tetras, 7 cory's, one pleco, and 4 fairly large snails. I like having a peaceful tank. I'm thinking of changing my current pump system. What is the best pump & filtration for keeping the tank clean longer? I'm going to be gone for a month and while I have someone to feed the fish, they don't want to clean the tank while I'm gone....