Good ole Lowe's.

First off, do not use any product from Lowes' HD o any big box store. Their exterior products are inferior.

Scrape down your deck. Sand to feather where neccessary. Powerwash with a solution of bleach and TSP. Let dry two or three days and apply an oil based primer made by Cabot's called Problem SolverÂ. Let that dry for 24 hours and then apply two topcoats of Cabot's Solid Decking Stain (you can use latex as it will repel mold better and give you better expansion)

This is a big job no matter how you slice it and is why I tell people to NEVER paint their decks. They always peel. if you follow the technique I outlined above you will get 4-6 years from your sealer. If you skip steps, you may get 6 months.