Welcome to our forum.
Personally, I hate the look of a tarp on a spa. I find it ironic that people put a tarp on a cover to keep it looking good. Do you really want the tarplook. I'd say, keep the cover clean and use 303 UV protectant on it.
What's 303UV? Never heard of it. Is it like Armor all?
Steve,It is because you continued to use the Armorall, and I'm guessing it was on a regular basis.