Before getting a pump have you had a chance to plan out your plumbing? Things like bulk head size or overflow size as well as number of elbows, check valves, total height, etc should be considered before picking out a return pump. Once you've got that down there is a head-loss calculator on the main home page. You can use this to give you a better idea on how big of a pump you can use. Hope that helps; if you already have it planned out feel free to share, seeing new setups come to life is pretty interesting.