Over the past couple of weeks my 9010 has tripped the GFCI several times. I have tried it on two different GFCI circuits. It does not always trip immediately. It may run OK for several days and then trip. This morning it tripped while I was sitting in front of the tank. I pushed the reset on the GFCI and it tripped again in about 5 seconds. I purchased this skimmer about a year ago. Any thoughts on whats going on? It was cleaned about 2 months ago, but I did not notice any calcium buildup at that time.