Applied two coats a year apart. Looking for advice on how to repair.

Hi, 

I had this deck built about 2.5 years ago in Rochester NY. The deck gets a lot of sun. I put a light colored stain on it at first and loved it. I realized the next year I put a interior stain (I'm not sure about the brand but the water did not bead up on it so I realized I did something wrong) on so I decided to re-stain, and darken in a bit. The second coat was applied in Spring of 2018 and applied it with a roller. I used Olympic Maximum stain. The color seems to have worn out over the past summer. I would love to start from scratch but I am not certain if that is possible/necessary.

Would you recommend chemicals to remove the stain?

If chemicals are the way to go...which ones? I have a Sherwin Williams nearby. 

Should I sand it with floor sander?

Using another product before applying more stain? using a different application method?

I would like to do this now. It is a rainy season in the 60-70's. Should I wait?

Thank you for taking the time to review my questions!