mildewed deck

I built a deck 3-4 yrs ago out of PT pine, stained with CWF after the wood dried for about 4-5 months. The deck is in the sun all morning. Last yr it turned black with mildew so I cleaned it with bleach and restained it adding M-1 mildewcide to the stain. Over the winter the deck turned black so I cleaned it last week and now it's on it's way to turning black again. Any ideas as to why and how to prevent/slow down the mildew? I've cleaned/stained many decks over the years but never had this issue. Even decks further south with dew that didn't burn off until midday weren't this bad.

 

Read this review... seems they have changed the formulation, and that mold it a reported issue with it.

https://www.deckstainhelp.com/flood-...-stain-review/

 

It's probably been 25 yrs since I've used the oil base version of CWF and I've not seen it being sold locally in 15-20 yrs. I used the waterborne version - https://www.flood.com/products/wood-...-finish/cwf-uv

 

Built my garage 30 years ago and last year is the first time I've had mildew on the north side.

Gotta be the weather.

 

It has been an awfully wet winter/spring and last year was the 4th wettest year on record. I've just never seen mildew come back so fast especially on wood that sees a fair amount of sun.