tank holes

[shanefee]

Hi all just got a second hand corner tank and wanting to put a sump on it its 200L. How many holes do i need to drill for the over flow would one be enough and how big would it have to be would a 50mm hole be to big. Thanks

[snailrider]

Congrats on the tank, Pictures?

I only drill one hole in my tanks. The size is about 1 3/4 inch. I do not run a high flow sump. If you don't want plumbing coming up over the tank edges you will need a minimum of 2 holes.

There are also a few different placement of the holes which can affect the flow also. You can drill the bottom or the back.

My 125g tank I drilled one hole in the bottom corner. I need to build the glass corner now which is going to incorporate an algae scrubber. My smaller tanks have holes in the back, with built in glass overflows and standard house plumbing to the sump.

[fsn77]

One hole can be sufficient for an overflow, however, you may find some comfort in having two in case one begins to clog. I like to use 1" bulkhead fittings, which most require a 1.75" hole.

Before you drill the tank, make sure the glass is not tempered. If it is, you'll end up with a big mess and no tank.