Mystery on the deck - what is going on here?

As always, there is always something that needs to be done; something that needs to be fixed or replaced and some times we just need to spruce things up.  This is the east deck.  The first deck I designed that spans 20 feet long and 14 feet out from the house.  There are steps just below the front of the picture and there are a set of stone steps off to the left that I rebuilt last year and made permanent with landscape adhesive.  There are 2 different types of deck materials used.  The upper deck where the mystery is located is the original 2x6 deck boards that we built the deck with in 2004; almost 10 years old they have started to show their age with twists, cracks, knots breaking and just general wear and tear.  On the lower part of the deck are composite deck boards.  These replaced the original deck boards a couple years ago and have faded to their light natural color.

I have plans to replace the upper deck boards with composite decking, as I did on the lower level, but those are expensive and so it is a matter of saving the proverbial penny for that purchase. 

So on Saturday as I sat on the deck relaxing and cooling off from working in the garden I started to evaluate, once again, the condition of the upper deck boards.  As I studied the area and considered my options, I decided to check the supply of paint that I had used previously when I painted these several years ago.  Most of that color has worn off and is gone.  After getting the box of outdoor paints down from its spot in the laundry closet I discovered I had less than a quart of the color that I had originally used.  Well shoot so much for that idea.  I didn't want to use the galvanized silver color I use for the propane tank and Wildcat purple was just too much with the purple sun shades above.  So I decided a good washing, sanding and sweeping would at least help to clear the yuck from the surface of the deck.  I checked the cat shed, yes I still had some deck wash left from the last time I washed the deck.  A little 409 on the area where the grill sits and that took care of those spots.

That looks better but now the side of the house and the screen door look even worse with their dirt splatters and paw print smears.  So those got washed.  One last look in the box of outdoor paint.  I wonder how much is in this gallon can marked Japanese Maple.  If you look at the picture you can see the faded remnants of that color which I used as my trim color.  The paints are mixed specifically for porch and high traffic floors like garages, with polyurethane mixed in to give it a water repellant property.  Maybe there is enough in that gallon can to give the deck a new look.  Wait and see what I finally decided but at least you know part of the mystery, something is changing with the floor of the upper deck.