Ok here is what I do: I use a dremel tool with a diamond tipped bit. I use these fittings to come out of the viv to drain:
Carlon at Lowe's: 3/4" Straight Carflex Liquid-Tight Fitting
I cut a hole just big enough to fit the fitting into the viv. Then I attach tubing to run into a 5g bucket.
I will attach a couple pics!