Thanks for the quick replies, I was a bit panicked. It was in fact a gfci but not what I have all my stuff plugged into, it's the first one in line on that particular circuit- with nothing plugged into it! Here's the story, in case you're interested; Started mixing water for a w/c, 3 buckets, each with a pump that I plug into on a strip with the rest of my sump, etc in my garage. Already realizing this was all on the same circuit, but never having an issue in the past with the exact same amount of stuff plugged in. So everythings humming along, then out of the blue that circuit shuts off. I figure I tripped a breaker, unplug the mixing pumps and go over to the panel to turn thr breaker back on, but it's not tripped! Here's where I got nervous, thinking there weren't any "easy" options left to explore. The oulets I have my sump, etc plugged into are not gfci (but are set up in a manner so as not to get wet, even in a flood of my system), but I remembered that if there is a gfci "upstream" on that circuit, and it trips, everything downstream will lose power. The outlet on that circuit closest to my panel is the gfci, and was tripped! Strange 'cause there is nothing plugged into that outlet. I reset it, and it again tripped when I plugged in my mixing pumps. I have no answer for this as like I said, I've set up identical to this multiple times, every water change. My only guess is that the pumps on my return and skimmer are in need of cleaning, I have not done that in a while...making them a bit less efficient, drawing more power, and pushing me over the edge of the .. upstream gfci? Strange.
Let me know if you have any other guesses. Thanks.