Hi, Ron (Boise staff of Aqua Pro) solved a 3-year old problem that escaped the skill set of 2-other local spa techs. I was billed about $1k to solve this problem (replaced mother board, 2-sensors, circulation pump) by the tech prior to Rons visit...and the problem persisted. My spa has been working correctly for 3-weeks now and I am confident the water temp will be a steady 104 when I want to use it. I met the people at Aqua Pro at the local Home Show and was impressed with the conversation. I would recommend this vendor. Chuck Weir