Hi @Tracylee,
Thank you for your question about finishing your treated pine deck.
The areas that you say have been marked by the pressure cleaner are where the top layer of weathering has been stripped back.
You may be able to use the pressure cleaner with a very focused jet to remove as much of the weathering as possible, but it is unlikely you will be able to get a truly uniform finish. Unfortunately, to get a uniform finish, you will likely need to sand back your deck.
You will need to start by punching the nails below the surface of the timber using a hammer and nail punch. Once the nails have been punched, you can use an Orbital Floor Sander, which can be hired from your local store, to sand the majority of the decking boards.
Any posts or intricate areas that can't be sanded with the floor sander can be sanded by hand or using a belt sander or finishing sander.
Check out How To Sand A Deck for some additional guidance.
Once the deck has been sanded, you can apply your choice of finish such as this Cabots 4L Aquadeck Natural Exterior Decking Oil.
I'd suggest checking out How To Oil Your Deck for some guidance on this process.
Let me know if you have any further questions.
Jacob
