[brooke]

I have a 55 gal, and at the moment only have 1 Maxi Jet 1200 running in the tank? I'm not sure if that is sufficient for filtration. I see there is some crap settling on the DSB. My question is how many powerheads should I run, and how ofter do they need to run?

[Reefland]

It isn't really a count of the powerheads, it's how much (random) flow you have throughout your tank. I would think that moving at least 20 times the tank volume per hour would be a good start, although some go for a whole lot more. So in your case, it wouldn't hurt to have about 1000gph flowing throughout it.

[ghofmann]

I'm running about 1400 gph between my 2 Hagen 402s and my return pump in my 55 and I still get dead spots in my tank.
The powerheads run all the time.
Not the greatest way to do things but that's going to change after the first of the year when I go with a closed loop and a couple of SQWDs.

[Reefland]

We have 2 Tunze 6060's, 4 MJ-1200's and our return pump in our 75 and we could use more in my opinion.

[ghofmann]

WOW That's a lot of flow in a 75! I was thinking of going with mag 12s for both the retun and the closed loop on my 55 and thought that might be bit much for softies and LPS so I may have to convert it to an SPS reef when I redo the system.

[Reefland]

I think if I were you I would go with a MAG 18. Put a valve on the output just in case you find it to be too much, which I don't think you will.

[brooke]

How do I know how many gph are flowing through the tank?

[Reefland]

By totaling the rated output of all your pumps/powerheads. If you are including return pumps or closed loop pumps be sure to reduce head loss.

[brooke]

I'm not sure how to figure "head loss." I have a Maxi Jet 1200 in the tank, and a Mag 7 for the return.

[Reefland]

Then taking a real wild guess, your probably getting about 795gph turnover. That is 295gph for the Mj 1200 and about 500gph for the MAG 7 return. I think adding 2 more MJ 1200's and a Red Sea Wavemaster Pro would be a very welcome addition.