I have a 20gal. long with just live rock (25-30lbs) and eshopps sk-100 hang on back skimmer. About 3-4 feet of head height and diy 10gal sump with cpr 50 overflow with aqualifter pump rated at 300gph. What would be a good return pump for this setup. It is a reef build so I will have corals. I've been looking at the eheim 2000 compact rated at 267-528gph. Is this pump to much pump to keep up with the 300gph overflow. Thanks in advance for any help with this. First time sump user and just a little confused.