for the first time since taking over my own pool, i'm thinking about putting the solar cover on the spa (no real need to put it on the pool since we're probably not going to use it any time soon i figure, but i use the hot tub a lot and trying to cut back on the energy and time it takes to heat it up when i want to use it). is there anything to watch out for, or any real downside as far as water balance goes to only covering the spa but not the pool?