Your other post made it sound like your were expecting devices that had similar or higher current draws to trip the breaker. There could conceivably be some electrical characteristics of one device that cause a faulty outlet to trip where other devices do not. This scenario is more common with AFCI’s than with GFCIs, though.
Like I said - it sounded like it was the pump; that was just an easy way to eliminate the outlet as a cause. Glad Abyzz was so prompt at responding and helping you fix the problem.
Well I will find out Tuesday when the replacement arrives. Fingers crossed. I don't want to switch pumps, if I did I think my second choice would be a red dragon.