I may case growout is 200 gallons tank volume and 175 sump. I use a Gen-X 6000 to circulate, so approx 1580 gph less head loss (5') is running thru the (8) 25 gallon tanks. Dispersed evenly that would be abot 7-8X thru each tank (less head). Seems to be plenty of water flow thru the system. I'm certain I can grow out 4000+ fish in there, have had it up to 2200 so far using half the tank space.