Hypothetical reef tank

[christyf5]

Originally Posted by Der_Iron_Chef

Couldn't you add ball valves (or whatever they're called) to all the returns, and dial the ones closest to the return more closed, with the ones at the end fully open? Tweak until you get even flow? I've also wondered about this, and it's the only solution I can work my mind around.

Thats what I was thinking as well. However of every photo I've seen, nobody has used ball valves or anything, they all look like Harveys setup.