Best way to remove solid stain from a deck

I applied sherwin williams deckscape four years ago. At least 80% of the boards have it peeling off somewhere on the board. GRRR. So, I have decided to re-stain the deck. I tried pressure washer but it will not lift off the old stain unless I use the 0 nozzle. That gouges. I tried 40 grit on hand belt sander and it works but took 10 minutes to do one foot on one board. with the boards not being perfectly flat i assume a floor sander would not work. I am actually thinking of removing all the boards and reversing them. Any recommendations?