I'm running the built in sump on the back of my 60 gallon DAS system and would like to add a sponge filter for additional filtration. I can only find the one I want rated for aquariums up to 40 gallons and then it jumps up to 75 gallons. I'm wondering which one you guys would recomend I use in my tank? Also If it helps I'm housing a few small discus in this setup currently and I've read they aren't huge fans of a strong current but prefer clean water should I over filter or under filter this tank either way it has the sump running most of the load and I will be doing partial water changes daily.