Overflow and return pump GPH???

e46mpower

New member
Hey guys. I am setting up my 75 gal tank and wanted to know what the proper gph I should be aiming at to go through my sump. I was thinking two overflow boxes that flow 800 gph each and a return pump that pumps roughly 1200 gph at 5 feet of head and my sump will be a 40 gallon breeder tank. Is this overkill, or you can never get enough water ciruclation? Thanks for any advice and opinions.
 

a4twenty

Premium Member
the common rule is 3 to 5 times tank volume for flow through a sump. this will help minimize microbubbles. you don't need to get all your flow from one pump. you can use a couple of powerheads in the tank to increase you flow.
 

Avi

Premium Member
I think that you'd be fine with that configuration. You can very well T-off the return hose from the pump for two outlets into the tank, one on each side. I think that you have the right idea to use two overflows rather than one since it both creates better general water movement that way and also lessens the already unlikely possibility of a flooding problem. Even with that configuration, though, you'd still benefit from additional sources of waterflow in your reef, bringing it up to a total of about 30X in gph the 75-gallons of the tank.
 

oct2274

New member
3-5x turnover is what you want for you sump anything more than that will reduce the efficiency of the sump and just be a waste. so for your tank you would need no more than 400gph for your sump return pump. you cannot rely on the overflows for the flow for your tank. the sump is there for filtration and will not work effectively at high flow rates. for flow you will need to add powerheads or a closed loop system.
 

flameangel88

New member
I've the same setup and would like to know which internal pump for the sump would you recommend for 400gph with 4-5ft head and 'low power consumption'? Thanks.
 

Avi

Premium Member
I don't know what you mean, oct, when you say that "the sump is there for filtration and will not work effectively at high flow rates." I can't think of anything that operates as "filtration," in my sump, other than the Chaeto that's growing in there. I have a 40-gallon sump on a 120-gallon reef with 600gph through each of the two overflows without any problem.

I know that there's a belief that a refugium should have slower flow rates but there's no hard proof of that, is there, that you know of? Anyway, the Chaeto in my sump/refugium is growing very fast, though I don't know if call what I have is really a high flow rate.
 

E-A-G-L-E-S

New member
except your skimmer ;) matching your overflow rate to your skimmer's pump makes for a much more efficient skimmer as long as the drain water is mostly directed to the skimmer....
 

oct2274

New member
also things tend to settle out in sumps = nasty stuff and if you have a high flow rate they just get stirred up and shot right back into the tank hehe
 

Avi

Premium Member
Well, I suppose consideration has to be put into the configuration of the sump. My skimmer is plumbed outside of the sump and the pump for it is in the "last" chamber of the sump which has a foam strip before it that's washed out every other day so nothing much get into that chamber at all.
 

oct2274

New member
actually you might wanna put the pump in one of the first chambers in the sump so it can do its job and pull the nastiest stuff out that the foam might try to catch.....thats kinda the skimmers job :)
 

futrtrubl

New member
It's kind of a myth that a fuge needs low flow, well at least for macro growth. There are papers on algal growth rate and flow rate which show that higher flow gives higher growth. I'll see if I can find one and post it. Also, about skimmers, matching the flow rates is really not necessary as you'll still not be getting all the water in one pass, or even cleaning that water in one pass, so you might as well keep nutrient levels consistent throughout your tank with better flow.

Edward
 
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