Seems to be 1/2" honestly. Thicker glass is harder the bend lol. 1/2" glass is strong. I've seen 700 gallon in 1/2 homemade. Never leaked. Crazy lol. I always think best to over kill haha
To all that can use a better deal. This tank is a monster in person and I cleaned it up very nice. I'm in the middle of touching up the stand for the future buyer.
Dimensions are same as 155 but this tank is 29" tall. Not 25" tall. For those who asked.