help us please, deck with history of mold and rot !

deck started molding/rotting within 3 years of it being built..come to find out the  contractor used mostly above ground lumber  which at that time , and now ,  seems to not be the industry standard , was told ( after the fact)  to use strickly ground treated lumber . ( by the lumber company that supplied the lumber )   

Fast forward...contractor turned his back on his  warranted ( ugg)  work, so  we did a good bit of wood removal/replacement/cleaning and  staining ourselves with an acrylic latex stain.  ( we've replaced about 40% of the decking ourselves , this is a BIG deck and has been a total PITA ) 

Obviously we did NOT get ALL  the molded wood so here we go again.

4 years  after our initial attempt of restoration   we now  have different areas on the deck that  we THOUGHT the wood was still good.  Did not  replace those areas  but cleaned them very well & stained it all   ,  now  we have more molding and rotting out in those areas.

Quick question. 

Lumber company that supplied the wood told us this :

"When replacing the deck surface, we  recommend coating the tops of joists with a brush on wood preservative to protect the holes where fasteners were removed and then using a barrier on top of the old joists to prevent water from collecting in old holes.

Liberally coat all the tops of the old joists as well as any other cut ends, holes, or other intrusions into the wood—including cuts or notches where posts attach to beams – with a suitable wood preservative product containing a minimum of 0.675% copper as oxine copper (copper-8 or copper-8-quinolinolate) or 1% copper as copper naphthenate. 

Grace Vycor Deck Protector or similar self-adhering non-metallic flashing is suggested to seal the tops of old joists. "

end of quote from lumber company 

I THINK since we use  a water based stain I should try and find a water based wood preservative  but.... I can't find one !

  Green's makes one but good luck getting it, even the Grace Vycor is near impossible to find.  

Advice on best alternative products appreciated !