Buying a tank to drill and light Q

I'll be purchasing either a 20 gal long or some other tank that holds a few more gallons, but the same footprint.  My question is should I buy a minimum thickness glass if I am going to have the tank drilled?  I don't see any stores that sell predrilled tanks that are that small.  Some of these small tanks seem to have such thin glass that I'm not sure if they can be safely drilled.

Odd thing is that the light fixture does have a piece of clear plexiglass on the bottom of it, yet the instructions say it must be used on a covered tank!

its just their way of cya with the company from you shocking yourself if it was to fall into your tank. I dont know anybody that covers their tank. The scary thing with thin glass and drilling is your chances of breaking the glass is high. Also if you manage to drill it with out cracking the glass the risk of the glass failing under the load of the water is high. I would say if you want a tank that small and not have the risks of it failing I would go with a acrylic tank. Just my 2 cents

See Eric at Aquatic Creations (posts to the forum regularly). He can build you anything you want and at the thickness you specify. Beautiful woranship.