Im thinking about drilling ooverflow holes in my glass aquarium...the only catch is that my tank is established (with an eshopps overflow unit-big box) and i dont care to remove everything from the tank...Im curious - have any of you successfully done somthing like this (or at least heard of it being done)...all the examples Ive seen have the tank on its side (so full effect of gravity on drill bit) and use flowing water (to wash away the dust)...I dont plan to attempt withought good knowledge that its worth doing...