2 - 1" Overflows Enough?

[Palster]

I had asked a similar question quite some time ago. I seem to remember reading that 1 inch plumbing will handle about 600 GPH and 1 1/2 inch plumbing will handle about 1300 GPH. Having two 1 inch overflows would be marginal and according to these calculations would handle 1200 GPH which would mean that if one of your overflows was to become clogged the other overflow would not handle the flow and possibly result in a flood. I ended up going with two 1 1/2 inch overflows on my previous tank for that reason. Have a look at my original thread.
http://www.canreef.com/vbulletin/showthread.php?t=31041