Wow, I would love to see your deck. I imagine that the wood is beautiful.
Do not use Thompsons or any product from Behr.
I recommend because I build decks and arbors for a living. The Flood Company puts out a good penetrating stain and sealer called CWF-UV. it also comes in clear. This would do wonders for your deck
One other Line of sealers that are great, but very hard to find. The company is Wolman developed by the same man that developed Wolmanized Treated Wood. They have a good line of products that will also do great.
Please since you have power washed the deck, make sure that it is very very very dry befor adding any treatment.