I bought my house 5-6 months ago and I think they made a new deck but I don't think so they used any protector etc. Seems like they installed and didn't do anything else, during winter time water was sitting in the deck and color got a little bit different now.
Can I use Thompson's Water Seal?
Would be enough if I use 1 gallon?
How often should I reapply?
Here some photos
Thank you