New tank overflow

[Mr_Banana_Pants]

I recently purchased a marineland 75gal tank with a corner overflow. It is pre-drilled with 2 holes. What do you think would be the best style and drains to use??? Is it worth/safe to drill a 3rd hole?

 

[mcarroll]

Shouldn't be any need for extremes.

Using the bulit-in 1" for drain and 3/4" for return will work.

At most, I'd use the two existing holes for drains (1 as backup) and run a separate 1.5" PVC line up to the top of the tank for the return pump.