I have a 75 gallon tank. I just bought some clear tubing from Lowe's, and put one end in the tank, and then suck on the other end to get the water siphoned, and then I lay it outside, and it drains pretty fast.
Then I bring the hose in to fill the tank.
Well, I don't have to do this anymore... It's a lot more complicated now with a trop tank, but that's what I did for my old goldie tank.