So i drilled my last tank no problems at all. Drilling my new tank. 3 of my 4 holes came out perfect. This only thing I can think of is the bit being to dull. But it was the 2nd hole on that bit and I only used a bit for 2 holes and discarded it. And the chip out is on the outside so I really was bamboozled when trying to figure out what happen but O well, it happened. The hole seals fine but my ? is, do you think structurally the tank will be fine? I just wouldn't want some how pressure be on any hole and it crack at this weak point or i don't know. lol Just seeing what you guys think?