What is a Good Way to Prevent Mildew on Covered Boat?

Factual Questions
1

I mean every year(in the Spring) I have to get bleach or something that is that strong to get that crud off my boat seats. I have heard of a light bulb but that seems dangerous.

Any other ideas? What about a bag of open charcoal does that work or is that a UL?

2

Move to Arizona?

3

But seriously–a quick check of Google under “mildew boat seats” brings up a bunch of stuff. You can get mildew-resistant seat covers, among other things.