what GPH return pump/closedloop pump ?

[BigTee]

hi to all...this is my first post, i have done a whole lot of reading here and i have learned alot. now i have 2 question? i am stumped as to which pump i should use for my return pump coming from my sump, aga 55g tank (48Lx13wx21H) DSB and cheto will be in this sump/refugium... pump will connect to a 3/4" hose barb nipple and 3/4" pvc piping going to the main display tank from the sump which is another 55g aga tank...(main tank)

question #2 closedloop system made with 3/4 pvc pipe, pump hieght 2.5 feet, pump will be on a shelf just under the main tank...i was thinking of a mag12 or mag 18 for the closedloop....will those pumps be to strong or good enough for my 55g tank?

what size pump for sump return and external pump for closedloop.....?
ty in advance for your help pics available if needed of closedloop and main tank...

[Hampton]

I would shoot for about 400 gph or a little less at 4 ft height for the return pump. For total flow, I've heard as high as 25X per hour for a Reef Tank, and about 10X otherwise.

[BigTee]

ty for your input for my return pump i guess a mag 5 would be good with a 4.5 foot pump height now would anybody have an answer for gph flow for my closed loop?

[hahnmeister]

For the overflow, Is use about a 300gph pump, with the head pressure, you should get about 200-250gph... which is just right. All you need is enough to skim the surface and send it to a skimmer in the sump.

For the main tank, I would be looking into something along the lines of 1500gph total turnover, but this is relative to the amount of outputs you are using for the tank. See, the more outlets, the less noticable each outlet becomes. My uncle likes seahorses for instance, so the flow needs to be minimal in his 40g tank, but he also wants to keep other things happy... so he uses a 1000gph pump... whoah! But its output is running to two spraybars that span the length of the tank on both the front and back, with about 100 little 1/4" holes in them... so the turbulence is very minimal... seahorses can fly around with ease, even thought there is 1000gph going through it.

Another example... a buddy of mine has a 210g with two, yes, TWO hammerhead pumps on it. Thats a total turnover of over 10,000gph!!! But you hardly see it because it comes out of 20+ outlets across the tank... many of them facing each other and cancelling each other out. OTOH, if all that flow was only coming out of two 2" outlets at each end of the tank, the tank would be a whirlpool.

So the gph of turnover is one thing, but how you use it is another. you could have 3600gph on your 55g and if you had it coming from 10 outlets, it wouldnt be so bad. OR, you could have one outlet with a 1000gph pump on it and actually get more flow.

Also, keep in mind nozzles and pipe diameter. 3600 gph coming out of a 3" pipe is alot less impressive than from a 1.5" pipe. One will carry a jet to the other end of the tank, and the other will make a calm flow. SEIOs look like they make alot of flow by volume, but when you consider that that 820gph is spread out across a 2" nozzle, the effect is somewhat less than if you were using a Maxi-Jet 1200 (300gph) coming out of a 3/8" outlet. The MJ will shoot farther.

I think that if you used a closed loop w/o a SCWD or anything... 1500gph would be good coming from 2-3 outlets across the back.

[flyyyguy]

Your return pump should be matched as close as possible to your skimmer as far as flow. The idea in mind is that if you match the return GPH after headloss etc with the same GPH that your skimmer can process, you will be sending as little unskimmed water as possible back to the tank.

[BigTee]

ty hahnmeister and flyyyguy for your info it was very helpful my close loop has two 3/4" pvc elbows in the tow front corners of the tank and my sump return has only one 3/4" outlet, so would a mag 12 with a 2' pumping height plumed externally be enough flow? and a mag 5 with 4'1/2 pumping height be fine? im going mixed reef i have a current usa 2 MH 150 watts and 2 130 watt compacs actinics (outer orbit)

[jmuscat2]

You are saying you have 2' of head on your closed loop because the pump is 2' below the surface of the tank. This in reality is not true. The only head loss you need to account for in your closed loop is the losses from pipe friction and the fittings. Because it is a closed loop the distance the pump has to lift the water is being equalized by the the height of the water above the pump on the suction side.

I'm not sure if I am explaining this very well or not. Hopefully you understand.

[flyyyguy]

jmuscat is correct. In a closed loop friction and fittings alone are all that add head pressure.

I forget the exact formula but roughly for 3/4" pipe you CAN add a foot to a foot and a half of head for every 90 degree fitting.