[Origami2547]

The OR2700 is a modified OR2500 with a needlewheel impeller. The OR1700 is a modified PH2500 with a modified impeller. It sounds like you have the bigger pump on yours. That, in my mind, would definitely explain why you had overflow issues earlier - because the pump was bigger than is now used. Of course, you draw more air through yours than mine - a definite plus in my mind. Good to know. I may have to try the larger pump someday (just for grins)....