how do i know if i need more water movement

[mightymouse]

i have my stock flter system pushing the water on a 36x18x12 tank. i watch closely at the algee and i see that none of it is staying still so i know there is movement all over the tank more so the closer to the nossel that deleveries the water back into the tank and move ment becomes less erratic the further. i hear that some corals like strong flows and others dont. if place a power head in my tank will it cause too much flow not allowing those corals that want low flow to flurish. i read somewhere that turbulent water movment is when coral flurish. PLEASE SCHOOL ME in the ways of the corals.

[Reefing Madness]

Minimum water movement for a fish only tank starts at 10x your water volume. A Reef tank water movement starts @ 20x your water volume. Example, I have a 240 gallon tank, I have 2 3200gph powerheads and 2 1200gph powerheads for a total of 8800gph.