I have to disagree with Elite on the external overflow. External overflows are more likely to fail than in internal overflow. IMO, the space lost by an internal overflow is minimal. It is nice to be able to sit your tank flush against the wall. It also helps minimize noise. I have a HOB closed loop system, so my tank cannot sit flush against the wall. As a result, it is noisier than I'd like.
My recommedation: Go with an internal overflow. If you are doing a closed loop system, have them drill for the closed loop system at the bottom of the tank so that you can sit the tank flush against a wall.
Minh
My recommedation: Go with an internal overflow. If you are doing a closed loop system, have them drill for the closed loop system at the bottom of the tank so that you can sit the tank flush against a wall.
Minh