Hi, this method only works if you have a drain hole in the side of the tank, the system came about because my drain hole was too high it was however large I therefore attached a large tube then thredded a smaller tube down the centre of the larger one, leaving the end of the small tube (in the tank) lieing across the bottom of the tank. The other end (small tube still) should finish twothirds of the way down the larger tube (a picture here would help but I dont know how to do that) anyway I finish by putting some filter material around the small tube, where it enters the large, and attaching the end of the large tube to a tap before putting it in a container! To drain down open the tap the larger tube will act like a siphon to the smaller tube which will take over the draining when the large one finishes. As long as nothing happens to interupt the flow the smaller tube will completely drain the tank! A drawing would so help to explain if you are interested I will try to do one! J