Water flow/circulation question

[Reefres]

I'm setting up a 120 gal. tank 48" x 24" x 24" with a center overflow box and want to ensure I have adequate flow and circulation in the tank. I'm thinking of running two pumps: One in a closed loop feeding 2 sea swirls in the outer back corners of the tank and the second as return from sump through chiller returning from inside overflow box to a "T" at top discharging to each side of tank. Is this a good design and will there be enough current lower in the tank? My other concern is location of inlet for closed loop. Is it best to drill a hole in back of tank or come out of the overflow box which I saw on a tank in this site? Also looking for recommendations on pumps. Thanks for your input.

 

[Len]

Reefres,

Sounds like a good way to plumb it. I have one of my return pumps feed a chiller too. I recommend Iwaki pumps because they are utterly reliable and powerful. I have a 120g also and use a MD30RLXT and a MD30RLT (feeds chiller first) and love it.

As for the closed loop inlet, you can do either. Using the overflow box (drilled near the bottom) is safer to prevent animals and plants from being sucked onto the inlet, but you have to make sure the overflow "grill" can handle the increased flow. Remember, if you draw water from within the overflow box, the grills will have to accomdate all the water that needs to spill back into it. If youre center overflow is 6x6", it'll be cutting it close. a 6x8" overflow will have no problem. Of course, you can always dial down the gph on the closed loop pump with a ball valve.