Sizing an internal overflow

[salmon alley]

I've got a 180g with two 2" bulkhead drilled about 3" from each other on the back glass.

I'd like to build a simple internal overflow box to over these bulkheads. From a flow-rate standpoint. I plan to use an AM3000 which should end up returning water at a rate of roughly 2000 gph, and I'll probably have a second pump to feed the refugiums which might return water at around 500 gph. So we're looking at 2500 gph total flow through the 2" overflows.

1- Will the dual 2" overflows be able to handle this?

2- How large of an internal overflow box (dimensions of box and width and depth of the teeth) would I need?

Much appreciated.
SA

[salmon alley]

ok...I feel a little embarrassed..:o

apparently the new RC homepage has an overflow calculator included with it!

For anyone interested in the answer to my post:

http://reefcentral.com/calc/drain.php?gph=3000&drain=Submit

[AcroSteve]

Not quite sure what is meant by the "Recommended minimum linear overflow size "

I recently built an internal overflow box for a friend. The pump was a MAG 18 and there were 21 1/2" x 1" slots in the box. The slots were 1" apart.

My overflow has 1/2" slots 1" apart and 1/4" slots between them. This box is 8" x 5" and easilly handles the 1000 gph I am putting throught it. I would guess it would handle 1400.

Just size up from this.

[barrettrhoades]

Hey. someone posted about putting in a built in overflow box. I am switching my 55 to a 75g acrylic tank, and I want to drill the tank and put in a built in overflow box. Will just one overflow be sufficient or should I plan on doing two? Does it matter if the overflow box is installed in the corner or the middle? what should I know to do this correctly. Any help would be greatly appreciated.

[AcroSteve]

I used 2. One is really a backup in case something would block the primary one. It is easyer and safer to totally get rid of the noise with two.