to drill or not to drill

[kylemagoo]

I have an Oceanic 120 about 5 yrs. old. I am thinking of drilling two-three holes in the back. I do not know whether the glass is tempered or not. There is a corner overflow with three holes already drilled.

Is it advisable to drill a tank like this? I am thinking of setting up a closed loop circulation system.

thanks!

 

[tkeracer619]

I would skip drilling it and add some propeller pumps to increase flow.

 

[runningnreefing]

Check with Oceanic to see if the sides are tempered. If they aren't, then drilling is pretty simple. Check out glass-holes.com, they have info about drilling glass.