Drilling holes in 180 gallon tank
I recently purchased a 180 gallon tank off of craigslist with the intention of drilling holes in the back and setting up a bean animal sump design. Well, upon receiving the tank and looking closely at it I found 3 marking that show the front, back, and bottom are all tempered. However, this marking is missing on the two sides of the tank. Does anyone have any insight as to the possibility of the sides being tempered as well? I tried to find a company logo so I could call them but there are no such markings on my tank. Here is a picture of said tempered logo.