I havent ever owned a tunze but have my JBJ hooked up and working for over 2 years without fail (knock on wood and crosses fingers) I am not sure I would like the fact that the manufacturer even states that the pump is "expendable," why is this? seems like a waste to me, should be an easier fix than ordering a new pump. But anyways I am happy with my JBJ.

Ooo PS: with any ATO if the feed line is submerged it will create/keep a siphon draining to w/e is lower either the tank or the ATO top off resivour.