If you're going to have external plumbing anways, why not do a herbie system with and external overflow box? Simple box on the outside with two drain holes - one for main drain and another for emergency. Then keep the drilled hole on the right side for a return. It would also clear out some space inside the tank.
I would personally go way bigger with the ATO. 2g is not enough. You would most likely be filling that every second day.
I've done a couple gravity fed ATO's, and I can say by the time you're done with the headache, you might as well find a used Tunze ATO for cheap.
__________________
They call it addiction for a reason...
|