Reducing starting current of semi conductor heat tape?

So, the acid test this morning.  I deliberately tried to let it freeze, by not running water for over 24 hours.  Indeed it did freeze over night, temps near -20c.  I plugged in Mike’s device, and within 3 minutes the heat tape would run on the inverter, and 7 minutes later the water flowed, drawing a total of ~45 WH of power!  MUch easier than lugging out the genny.  I’m going to wire up a dedicated outlet for the heat tape so I can simply throw a switch inside and energize it.  

It would probably take ~twice as long if it had been fully frozen throughout it’s length.  

Once again, thanks for all the help,

Tony