Water Movement For SPS?

[myreef]

I don't know what a minimum flow would be, but since I installed two closed loops, my SPS has done much better. I now have 22-34 times movement in my tank, depending on the timers. I read once that mother nature, during a storm, can move water 50-75 feet per second. If they can survive that, I highly dout we can have too much flow in our systems. However, like you said, it needs to be alternating. If you blast a SPS coral out of a return then I would bet the polyps would not open. I haver 2 closed loops that alternate every 6 hours. Giving right to left and left to right water movement. This, coupled with my two return pumps, give great motion. I would say if you have a predominately SPS tank, I would shoot for 15-20 times movement or more. HTH

 

[2poor2reef]

I haven't found the max yet. I recently set up a 15g sps tank with pocillopora, acropora and pavona sp. which turns 60x/hr. 2/3 of the movement is via closed loop mounted 1/2 inch stubby sea swirls, the remainder via spraybar mounted on sump return. The sea swirls have flared nozzle outputs and deflect off the opposite glass so there aren't any strong direct flows but the overall flow is very large. The only sps I've ever lost in the past were due to insufficient water movement.

 

[XXX]

I know SPS need a good current and preferably alternating in nature. But what are the boundries as far as minimum flow and maximum flow? Will a medium current cause the SPS to just grow slower and have a different look, or will it cause them to be unable to survive?

Thanks