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I am thinking of doing the same...but I am a bit concerned about the heat that builds up under the cover in the summer..Running both a pool and a tub gets expensive!! I know they say you can prop the cover with tennis balls to vent the heat, but I wonder about bacteria growth in any water that remains in the tub...
Where you moving to Zep. Out of town or just a new place. Just curious! Also, do you plan to get a new hot tub for your new place?
Or, you could just turn it to your eco mode, turn the heat off and use if for a cool tub! How much do you think you save by having it empty? I would contact my local dealer (where you got the spa) and ask if they have had any issues with spas that have sat dry for months.