I know that the black staining is a pain, but for me, after buying cheap, big box "pressure treated" lumber which rotted within 4 years AND I could NEVER get ANY stain, even Deck Over, to stick to, the black staining is easily taken care of with a 3-1 water / bleach mixture.
My 10' X 20' deck takes me an hour, doing a 5' X 10' section at a time. Use a garden sprayer, soak the area with the bleach mixture, let it set for 10 - 15 mins keeping wet the entire time, I then lightly scrub with a push broom and a bucket of hot water and Dawn dish detergent then rinse with your garden hose. Done and good for another year. Everything requires SOME maintenance.
Just cleaned this one still some wet spots, but came up nicely.