217 days of sunlight for SC, 286 for tucson. Also the light has more energy in Tucson:If I take care of them, I can get three years out of them. I purchase them online for half of what I would spend locally. It would seam that the sun's intensity would be similar here, though we are not as hot or dry. 2-3 tarps a year is outrageous. I would not use them either. I wonder why I can get three years from one, and you would get one year with three. It is not UV. That is interesting.
I have similar problems at my place--we are that orange area just up from the Delta in California.
Plastic water fountains do not last a summer here. It is likely worse in Arizona for sure.