drilled overflow

[Apostle]

Not sure if this is the right place for this post but here goes anyway.

I'm in the early stages of planning a new tank. looking at a 5 x 2 x 2.

I want no equipment inside the tank at all if possible, not even an overflow box. So i'd have to have the tank drilled. This is where my knowledge is a little limited. Would I need to have an overflow weir made or could I go without. If so what would be used to cover the overflow hole(s) to stop fish heading for the sump?

How can I work out the flow rate into the sump. I take it, it would depend on the size of the drilled hole as well as it's depth. Can anyone give me any advice or recommned any articles.

Thnaks is advance

[Kentanner11]

you would want to have an overflow system (the riser tube, elbow, and screen) not just your bulkhead. drsfosters and smith have a complete overflow/return system for under $50. IMO I would go with bigger holes than required. If this is for your 60 g. I would go with any where from 1"-1.5" (bulkheads) your holes will have to be bigger than the bulkhead size though. Hope this helps!