Help me with my sump

[Chief Hill]

Originally Posted by reefwars

biocubes are easy to drill when stocked, just drain out the back chambers and drill away, ive done loads of them

id never trust a syphon overflow ...thats scary:P

I never really considered just emptying out the chambers a bit.
If I were to go that route and drill out 1 hole in the 3rd chamber how far down from the top should I drill? And what size would you suggest. Something to run 1"OD pipe?