Great Information Greg. Id like to add one thing though...
with tanks that do not have "predrilled" holes, and for people that have to use hang on Over flow boxes....the simple fact that syphon failure is a scarry thing is enough to turn me off to the idea....BUT.....
what if I was to rig a
Float switch up so if the HOT overflow box were to lose its syphon...once the water in the main tank reaches a certain level it turns off the Return pump. This would avoid the disaster of 10-30 gallons of water in your living room..... would this work????
just something I may do ....need feedback first