what size overflows and return?

[salt2o]

Hello all. I am trying to decide on the sizes necessary for my overflow and return. I have a 120 gallon 2x2x4foot. i want to drill an overflow on each end of the back wall of the tank and i want to put a single return in the middle of the back wall. does this sound like a good idea? What sizes for each would be recommended? I will have a 40 gallon sump under the main tank with approx. 1500 gph circulation. Also any advice on where to purchase the diamond drills and sizes needed?

 

[ahayes13]

why not just do one overflow with two drains in one place. instead of making two ? i have the same size 120 and mine is like this and i really like it. my return is pvc back up to the tank and in the middle.

 

[Eggs]

I have a 150g with the same foot print as your 120, and have 1" overflows on each end, with one 1" return in the middle - I like having two overflows so I can skim the water surface from each side. Seems to work.
IMO, 1500 gph may be on the high end - not much time for your protein skimmer to do it's thing.
I bought my diamond hole saw from here - relatively quick shipping from Hong Kong. Good value for the money:



eBay Store ? THK Diamond Tools: Search results for.

There's also a web site, but I couldn't connect to it: www.thk.hk


Others have bought from here:

Glass Hole Cutters - Glass-Holes.com dope aquarium stuff

 

[salt2o]

I have an ETS 600 skimmer. Its a downdraft style that requires 1000gph to operate. Although I will have a seperate 1200gph Iwaki powering this, the 1500gph Iwaki is strictly for circulation of the main tank from the sump. The sump will be gravity fed. I want to spilt the return and point them toward the live rock.

 

[Eggs]

I thought the 1500 gph return pump (circulation) may be too much, not the skimmer pump. Your circulation pump does not have to be higher than your skimmer pump.
I have two tanks each with a 1200 gph that feeds the skimmer. One tank (180g) has a return pump (circulation) around 1100 gph The other is a 150g (mentioned above) with a 700 gph return (circulation) - which is probably too low (I've been meaning to change the pump and go up to 950 gph return (circulation).
I think your good with the skimmer and it's pump, but the circulation pump at 1500 gph maybe on the high end. Keep in mind that you'll have to drain at least 1500 gph out of your display tank, or your sump will run dry and your dispaly will overflow. If you want to run the 1500 gph, you need to calculate how big your overflow holes will need to be (there's a chart out there somewhere I could find). The overflow from the display tank will determine the max. gph of your return pump (or circulation).
You could always try it and see what happens, just put a pvc "T" with a valve above the return pump in case you have to cut the gph down.

 

[Harry_Y]

I run Two Glass-Holes 700 GPH Overflows on my 180

700 gph Overflow complete kit - Glass-Holes.com dope aquarium stuff


I was originally going to use one in the center.

After discussing it with some of the local reefers here
I went with two on the sides since it looks nicer.