I found a website this morning before going out to buy products for
deck cleaning and deck restoration. The author claimed any oil-based
stain will contribute to the growth of mildew in pressure-treated wood.
He suggests strongly buying a "resin-based" stain, and a search for
that term on Google, Yahoo, and other search engines turned up warnings
that popular brands of stain contain only 5% resin.

So-- Where can I buy resin-based stain or protectant? Any suggests of
websites or particularly of stores in the Northeastern Pennsylvania
region Greatly appreciated.

Most stains have anti mildew agents in them. My deck stain does not
mildew much but where it is worn off to wood , the wood does. Go to a
real paint store talk to a pro about what they have. There are also anti
mildew additives you can buy . If it occurs a bit of bleach sprayed in
garden sprayer will kill it. Im in total shade so I use bleach alot or I
would have black concrete walks.