Drilling a 210 gallon Acrylic tank

[pfcbizz]

I'm looking to do a reef tank with 2 overflow towers made from 4" PVC pipe and the drain and return in the far ends of the tank and I plan to drill the holes myself, but I want to know what size holes I need to drill for the bulkheads for the overflows, return and drain ?

 

[Waddi]

I would bet that if your trying to drill the bottom of it, it may be tempered, so you try drill a little bit of it the whole sheet that spans the bottom will crack the whole pane of glass. You should look into if its tempered first

 

[BL1]

Are you planning on using 4" bulkheads? The biggest ones I was able to find are 2" ones.