A tub that’s 3x the size does not require 3x as much power or 3x as much maintenance.
It stands to reason that it takes three times as much power to heat up a 600-gallon hot tub than a 200-gallon model, and you’ll need three times more chemicals to balance the water at the start-up stage. But that’s just true for the first day, at initial start-up.
Once the hot tubs reach max temperature and the chemicals are properly balanced, you might be surprised at how little difference there is when it comes to power consumption and chemical use, due to the laws of physics related to mass.
Smaller hot tubs cool faster, and they actually need more monitoring and more frequent chemical maintenance than larger hot tubs because the chemicals deplete quicker. So, don’t think that a bigger hot tub means a lot more work and a lot more cost to maintain.