How often is it tripping? Just once in a while or common? If it's common, just like Chad said: unplug things one at a time and test it out. If it takes a long time and unreliable, you obviously wouldn't want to be doing this with your main return pump or other critical pieces. Try to get a volt meter and see if you're getting lots of stray electricity both inside and outside the tank. Might purchase a Kill-a-watt for more information. Even if it doesn't pinpoint the problem, you'll learn what items are drawing however much power.