Just, drilled another 10 gallon tank with the Hong Kong drill bits...two holes, no problems. My routine: Make a hole thru acrylic sheet or thin plywood for a guide hole, clamp it to the tank, and on the other side of the glass I have duct tape and a very thin piece of ply wood, all clamped together. My thought is that the plywood gives more support to the glass. The duct tape holds the glass and keeps it from chipping. I took about 20 minutes a hole, watching for water to drip down into the tank that I had broken thru. I poured water on the hole throughout the process. If you are on the fence about drilling your own, just read this thread and go for it!