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Results are I lose approximately .75 degree F per hour with an outside temperature of 69 degrees.
Thanks Vinny. That makes sense. One thing I could not figure out is that with my Arctic (perhaps this is common) if the current temp is 2 degrees above the set temp, the pumps will not come on (so no filtration) so that the tub will not go too much higher than it was set to be at (the pumps definitely do increase the tub temp). So I wonder how Bosco set his so the heater would not come on, but it would still have pump cycles?
Wow that seems abnormal to lose .75 degreea an hour w/ your cover ON.. I also have a Jacuzzi. It was 28 degrees the other night and I soaked for 1 hour with cover off and temp. remained constant.Today temps reached the upper 50s and my water remained at 103 all day. Check to see if your cover is tight all the way around.