Advanced Aquarist has published a whooper of an article this morning. The authors set out to create a standardized method for measuring propeller pump output and tested all the popular propeller pumps on the market today.
Feature Article: Experimental Comparison of Measured Flow Output of Aquarium Propeller Pumps; Advanced Aquarist's Online MagazineHobbyists have seen significant advancements in the range of aquarium circulation pumps available over the past decade. While all manufacturers provide a flow rate for the pumps, it is not clear what methods have been used to arrive at the numbers. Further, different manufacturers may use different methods. We have presented a standard method that we hope can be adopted by the manufacturers thus enabling a more accurate and verifiable approach.