indycoltsfan

Hello, I have a question regarding my spa filters. I took the filters out of the spa to clean them by soaking them overnight in the filter clean solution (I put new filters in the spa while I was doing this). I soaked each filter (2) overnight, let them dry, and placed them in bags so I could use them to swap with the filters in the spa the next time I needed to clean them. Well, over the weekend, I pulled them out to use and noticed that each filter had some black spots on it, which I assume is mold. I tried resoaking the filters overnight and it seemed to get rid of most of the mold but not all. I'm afraid to use these in the spa. Some questions: 1. Is there another way I should try cleaning these filters to get rid of the mold, or are they a total loss? 2. How can I avoid this in the future? I read most people have multiple filter sets so that they can swap them out each month so one set can be cleaned while another set is in the running spa. Obviously they weren't totally dry when I bagged them; how do you guys clean your filters? Thanks!