Lakeside PT wood deck In upstate NY

Need pics for prep help.

@deckstainhelp photos:

Dear Scott,

Please see photos of the deck. I rented a floor sander, started with #60, however the sander isn't working very well (although it may be the user!) as not much is being removed. I plan on returning this machine and renting another. I'll try a coarser paper as well. Any guidance from you would be welcome! 
thanks,

Kathy

Is that paint or a solid color stain? You do not need to remove all of the old solid stain (just what is loose and peeling) if you plan on going with a new solid color stain in gray. See these tips:

https://www.deckstainhelp.com/how-to-apply-a-solid-color-deck-stain/

Tips here on how to sand a deck:

https://www.deckstainhelp.com/how-to-sand-your-wood-deck/

ARMORSEAL® TREAD-PLEX Water Based Acrylic Floor Coating

Deck Gray

Calcium Carbonate ≥10 - ≤25 1317-65-3

Titanium Dioxide ≤5 13463-67-7

2-Methoxymethylethoxypropanol ≤3 34590-94-8

Carbon Black ≤1 1333-86-4

Heavy Paraffinic Oil

I would be relieved if in fact I don't have to remove all this paint!

Thanks

Kathy

It doesnt really say, but it does look more like a paint than a solid stain. Sand off as much as you can then use a solid-color deck stain in gray after:

https://www.deckstainhelp.com/what-are-the-best-solid-color-deck-stains/

Dear Scott

More questions...should I use the cleaner and brightener with power washing prior to staining?Thanks a million

Kathy

After sanding, yes.