Drilling my tank

[alyxandria]

Will I be ok with just one overflow hole from the overflow box? I have a 700 GPH overflow box.

Looking online, I see most people going with two. Will I be able to get away with just one?

Another question... I'm going to go with 1" PVC so what size hole saw should I use and what size bulkhead?

[Tobykourtney]

I would do 2 holes. I would only push a 1 inch bulkhead to 300 gph max. I have 1-1 inch bulkhead on my 20 high and anything over 250 gph I can't even run a strainer or my tank overflows. If you run 2 holes you can use 1 as a siphon drain with a gate valve and the other as an emergency and easily get 700 gph.

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[mr_X]

I think you are fine with a single hole. Just use a 1.5" bulkhead. Glass holes 700 gph overflow has it set up just like that-
Aquarium overflow box 700gph

[alyxandria]

Originally Posted by mr_X

I think you are fine with a single hole. Just use a 1.5" bulkhead. Glass holes 700 gph overflow has it set up just like that-
Aquarium overflow box 700gph

Thanks! That link is super helpful.