I had a break thru. Instead of trying to heat whole tub, just heat 5 gallon bucket then have bucket bath or shower. 5 gallons was enough for wife and me.
Started off at 48F, set thermostat to 135F, it gives some beeps to notify its reached temp. That ended up being way too hot had to let it cool down a bunch. Didn't take long to heat at all.
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