Hi. I have a new red cherry shrimp aquarium and I was wondering if there is any point to cleaning my sponge filter once a week when I do my water changes? It looks like this after 5 days. I heard shrimp like eating from it so I don't know if it's counter productive. Would I clean it in tap water or dechlorinated water? Also I was told to do 25% water changes weekly by my LFS. But then I read online that I only need to do 10%. What do you think? I have 6 shrimp and a few baby snails.