Best protein skimmer for 75 gallon tank

Mostly size. I wanted a cone, and I only had 8 inches of sump/fuge to fit it in. The eshopps gave me the sicce pump and a 6" dia cone design with a footprint that BARELY fit in. It is way overkill for my 75 gal + fuge setup, though ( only a small yellow tang and small o. Clown for now). Its dead silent and has done some great skimming though. Id recommend it, though not for a 45, think they have a smaller one that would probably work better for that.

 

Perhaps an AquaC Remora Pro or a Reef Octopus BH1000 for your 45 gal...