i have a 180 gallon tank that i want to drill only problem is that i am not 100% percent sure it is not tempered. i can not find a tag or anything on the tank that ciould tell me that it is. i did a polarized test that i found on youtube but again i am not sure. i am pretty sure it is not tempered. is there someone in san antonio that can give me a hand on drilling it or possibly drill it for me. please let me know