water volume from overflow box

[jdair101]

Hi everyone
I currently am using a LG 3mdqx-sc pump for a return pump, but want to flow more water. I ordered a new Mak 4 from Saltwater Connection (could not pass up the price) and want ot use it for the return pump. My question is will my single 6X9 corner over flow be able to handle the extra volume of water. I'm using a 1 1/2" durco stand pipe aswell but there was a post that says that it should handle something like 1600 gal.
tifn
Thanks Jim