I was given the advice of enjoying the pools as following: dry sauna until I couldn't stand the heat, quick plunge in the cold water, then a soak in the tepid salt water. Every time I encounter a cold water plunge I think of a million things I'd rather do instead, but I took the advice and didn't regret it.
I got a salt scrub and Elisa did the deep tissue massage - both of which were excellent and I'm pleased with the softness of my skin. Despite what I consider to be kind of a pretentious looking entrance, it is very laid back and relaxing environment. There's also a Vodka bar next door that we'll have to try on our next (evening) trip.
If you're looking for a good way to get a break from the cold, gray Seattle winter, I highly recommend Banya!