Not sure about everyone else.....but I've never deducted out water displacement for calculating turnover rate. Like jostafew said I'd use 3750 as a base......if not higher

This could be important. Any advise?

I don't know. Technically I should not be able to keep any SPS judging from everybody requirement on flow, but I do keep them successfully and they grow fast too, and I bearely have any flow. I have 2 Koralia Evolution 1050 in my 75 gallons on each side, pointing at each other. There is only a gently flow and some SPS bearely move their polyps, yet everything as been growing steady for almost 2 years now. Birdnest, acropora, pocillopora, montipora etc...all grow well and have great color.

If your water is good and the corals have good plankton and food in the tank to feed on, they will grow even if you don't have the best flow. So it's probably good to have higher flow, but when I tried to put the powerhead more directly at my SPS they retracted their polyps and did not seem to like it.

So how many GPM would your two pumps produce, any Ideas?

I have had low flow forever and have had great luck with all coral (including 1 birdsnest) so that's why idecided to go down the SPS path. If I could get an idea of your flow that would be great, thanks

I don't know but it's very gently flow. Check out my tank video and that will give you an idea. The strongest current is at the top left of the tank where the right side powerhead shoot its flow. Since the left pump has a piece of liverock over it, sort of, it does not shoot a lot of flow on the other side.

Watch at 720p please :)

http://www.youtube.com/watch?feature...&v=AvkIATAzV5Q

Nice! Great tank. Now I'm feeling better about flow.