my point was that you can't verify flow within a tank by GPH, it's a good starting point however. you could have 600GPH within your tank which may seem appropriate but depending upon position and/or direction of the water flow source(s), the rest of your tank may be suffering from stagnant areas. everyone constantly uses the turnover rate as an exact science in trying to figure out the flow for an aquarium, which it never is....you can add up your powerheads, returns from your sump, a calcium reactor or protein skimmer, etc. and try to assume your GPH. it's just a number, probably not the true turnover rate...as long as your tank is healthy and all of your inhabitants are happy, forget about the numbers. this is just my opinion of course. _________  |