I live in west-central Florida and would like to put a cover on my hot tub. It does get cold here in the winter (25 is cold when you have coconut and royal palms) I use my tub year round due to severe Restless legs syndrome. The bubbling water overdrives that unpleasant sensation). The issue I have is with my two cats. They like to spend the days out on the pool deck. Unfortunately, despite having a Cat Genie litter box (washings itself and pumps the waste into the sanitary sewer) in a bench box with an access door on it, one of my cats will occasionally pee and poop on any large flat horizontal surface. Obviously, I do not want to build something that will turn into a makeshift litter box.
I would appreciate any helpful suggestions that do not involve shooting, hanging or otherwise killing the cats.