I want to put my pump on a timer and have been reading the posts here, but all seem to deal with hard wired timers. I was looking at Home Depot and they have heavy duty outdoor timers pretty reasonably priced. They simply plug into the outlet and plug the device into it. Just what Im looking for. I have a AG pool and my pump has the standard 3 prong plug thats plugged into a GFI outlet.

Any harm in using one of these timers?
Thanks
John