I have a 180 running a Via aquaskimmer Model SK-200 - manufacturer rated for tanks up to 100 gallons (this rating is VERY CONSERVATIVE). Includes Via aqua 2300 pump rated at 609 GPH. Dimensions - 8" X 13" X 17" Highand it works fine .
I would reccomend it
for the price Currently $90 on e-bay You cant go wrong.