Decided to drill my tank

[WarDog]

I would recommend using the Herbie overflow method. When set properly it is silent and safe. Others may recommend a Bean Animal drain, this will require one more hole than a Herbie.

http://reefcentral.com/forums/showth...erbie+overflow

http://gmacreef.com/herbie-overflow-...method-basics/

For a 75 gal system I would go with a 1" main drain, a 3/4" or 1" emergency and at least one 3/4" return. You could also do two 1/2" returns, or even one 1" return. However I think the 1" return would be too big.

A 1/2" bulkhead requires a 1 1/4" hole

A 3/4" bulkhead requires a 1 1/2" hole

A 1" bulkhead requires a 1 3/4" hole

You will have to identify whether the side or bottom you wish to drill is tempered or not. Tempered glass cannot be drilled.

Hope this helps.