Flow in tank

[groan]

I have 2 massive powerheads in my little 75 gallon tank.
I have a Chinese model I got from pat that puts out a whopping 1500 GPH. it's like 2 koralia 3's in one.
I also have a Koralia 4 that puts out a shopping 1200.
like this


Now I have read that if I get 15-20 x turnover that is good flow.
if I do the math, 75x20=1500 so should I be good with just the Chinese double headed dragon? If I have both on i get WAY too much flow.

what's your thought?

I have smaller Koralia's I can put in if need be but the water push from the Chinese model is really nice. I have it at one end and pointing slightly up it moves everything quite well.

[Severum]

It all depends on what your trying to keep...

I have 2 K4s in my 120 fish only along with the return pump. Thats at least 40x turnover. Maybe a little overkill. 

[groan]

I'll be keeping a bit of everything.
LPS, and hopefully SPS. I dont want them to look like they are standing in gale-force winds
heh

I'm mostly curious if people think this is enough flow.
Oh also I do have the return pump. it is set reletively low as I want the water to cirgulate through the sump slowly. I don't knwo how much flow it is getting. Hard to guess. I have the valve 1/3 closed, approx. and I have no clue how much flow the pump gives out of the box. (i need a new pump!)

[mikerobart]

Depends what you want to do.... and the amount is not necessarily as important as direction and coverage. You're trying to avoid dead spots and get flow adequate indirect flow (and ideally random) to all parts of the tank. If you're going fowlr it's probably enough, if it's lps may be good with right placement if you're not blasting them directly, if sps dominant that might not be enough. It's a tank specific thing though you have to see how your  rocks are placed and how the corals are responding and what detritus is doing is it settling all over... etc.

When I finally get around to being fully barebottom and sps dominant on my 90g I expect my mp40w and 3x k3's *might* be enough until I get another vortech or some new hydor evo's on a wavemaker or something ,

[mikerobart]

LPS you usually get better polyp extension when they are not being blasted but if polyps are swaying nicely and you are not collection detritus you are probably a-ok.

[groan]

Thanks,
I'll monitor and see how it goes.
I noticed the hammer coral was swaying nicely with the odd gust so it seems pretty random with cross currents from the flow across the top that comes back from the other side.
The nice thing with teh Koralia and knock-offs is that the flow is dispersed from the head. it flows in many directions which gives the tank more current in more places instead of a jet like a maxi might do.