[quote=vanreefer
My design... advice when drilling through glass... make sure the chuck of the drill doesn't smash into the back of the tank when you are drilling... then make sure the place that cuts the replacement piece of glass cuts it to the correct dimensions or it will be 2 months since you got the tank and it still only has 3 sides GRRRRRRRRRR[/QUOTE]
Don't know if you can make it out
The drain is a 1 1/2" bulkhead on the bottom of the tank the pump is mounted on the underside of the tank and it returns to the tank via the manifold on the back which has 1 1/2 split into 4 x 1" with ball valves to balance the flow
if you want to pm me your email addy I could send you the image in a larger format