My Arctic Spa sucks!! Worst tub I've ever owned. I have a single pump Fox with the Onzen system. Tub constantly overheats every time the tub goes thru a filter cycle! Arctic's answer is to buy louvered doors! This tub was sold to me for year round use, but it won't work in the summer as supplied to me. With only very light use I can't get the tub to filter enough to keep the water clean. As soon as it overheats the filter cycle locks out. No filtering thus water becomes dirty and smelly and I have to dump it and refill with new salt at $ 60 a pop for 10 lbs. Total ripoff!!