Old Oceanic 75 gallon.

[Roberth101]

Just wondering if after Oceanic drilled the bottoms of there tanks did they temper them? Asking because i only have 1 drain and i want to drill 1 more for an emergency drain.

 

[LiveWire]

If I were to take a guess I would say its tempered as it would break much easier especially after drilling holes in it if it were not. Most likely the sides are no so you could drill one of those if that helps. You can also try the polarized glasses trick. I have heard about it but never done it myself so maybe someone heer can chime in on if it actually works or not.