you can never be overfiltered!!! Also it depends on your scaping as to were and how many dead spots you will have. depending on fish choice will determine what flow you want. I see you have discus and I am sure you know they like very calm waters. If this is your plan I would definatly go with an eheim filter of some kind. They have very large bio areas that are essential for discus and low flow rates but very powerful pumps.