The SmarterSpa requires no spa modification. Simply attach the control panel to the Spa skirt, add about 1.5 cup of salt per 100 gallons of spa water, drape the cell over the side into the spa water and plug it in. (In line kit sold separately) The power supply uses 110 / 220 VAC and outputs a low voltage 5Vdc to the Cell.
The SmarterSpa doesn't operate on a timed cycle like all other salt chlorine generators. The SmarterSpa is the only salt chlorine generator in the world with chlorine detection built into the cell. Traditional salt systems turn on at a fixed cycle which is called the power level, They turn off if they need to or not. The SmarterSpa measures the chlorine, and when it needs more it will start a chlorine generation cycle. Even if you set the chlorine production to maximum, it will not turn on unless the spa levels are low and will not over-chlorinate your spa. LESS MAINTNACE AND LESS CHEMICALS.