180 Gallon Bowfront Overflows

[reefveterinarian]

Hi,
I just purchased a used 180 gallon bowfront aquarium that is going to need to work before I can get it up and running. It currently is drilled for a single overflow in the right corner but I am considering adding an additional overflow in the left corner for better water filtration down to the sump. What are your thoughts on single vs. double corner overflows? I am also curious if you have recommendations for the overflow set up? I have a picture of how it is currently set up (the return is the top hole in the current configuration). It is drilled in the back since the bottom and front are tempered glass.

 

[takitaj]

More likely than not the bottom is tempered. If it is and you attempted to drill it then it will shatter explosively into tiny pieces. If so the hole(s) in the bottom glass were drilled before tempering. There is a good chance the side panels are not tempered but still possible so before doing any drilling you should be sure that they are not. You can find a bunch of videos on youtube that explain how to determine if glass is tempered or not and also on how to do any drilling.