Drain Hole size

[fish head]

I am building an 84x24x26 tank with a single overflow in the middle, as apposed to two overflows; one at each end. The one middle overflow idea will allow more side viewing.
How large should the hole be in the bottom of the tank? Should I drill one large hole or two side by side? How big? I will be using a duriso stand pipe. I want to eliminate the chance that the drain plugs and overflows the tank. Plus I am concerned one large hole may not be enough when using a stand pipe.
Any suggestions?

 

[richard rendos]

Your tank will be 226 gallons when finished. I would use a 2" bulkhead (I think it will require a 3" hole) or two 1 1/2" bulkheads. That should allow for plenty of flow to your sump.