You can never apply a sealer over a deck stain so you will have to remove it by stripping and or sanding. You will probably have to restain after as w...

Sorry for the delay. Yes, use a cleaner and then a wood brightener while pressure washing. Stain after:

Sorry for the delay. Just paint over it.

Sorry for the delay. See this about new wood:

Sorry for the delay. 60, then 80, then brighten.

Try TWP Stains but you will have to fully remove the Sikkens first,

You have to remove the previous coating when switching brands. Try the TWP 1500 after removing it.

The shelf life of opened containers is usually about 12 months or less. It will probably not last any longer.

Thanks. Deck finished. Looks good and I hope it will not peel next year. One more question regarding the left over stain. I have 3/4 of the can lef...