Welcome to another episode of BRStv Flow Dynamics, where each week we dig into various pumps to show you a visual representation of their flow pattern to help you make a more informed decision on what will work for your tank. Hydor Koralia Evolution pumps are one of the most popular pumps on the market - and for good reason. A reliable pump at a cost effective price presents a very valuable pump for those looking to move water in their tank, and is why BRS recommends them. Evolution 850 Power Usage - 4.5 W Dimensions - 5.5" x 2.5" diameter Maximum Flow - 850 GPH General Tank Size Recommendation - 50 gallon