Well went to work this morning, and what happened? nothing, the vibration wasn't there. I got through all day until the afternoon it started again. I am starting to think it might be the water getting a little warm in the tank. It is really noticeable after putting down the wand for a minute and letting it run in bypass while I move something or go back to the truck. Also the hose sitting on the lawn super heats the water. All I know is there was no vibration for the first few hours which tells me the pumps ok. Now how to keep the water from getting warm. The water out of the tap around here is 70+ degrees.