Bluestone is a very dense stone and sealers will not penetrate. It will be more a topical coating. We don't seal any of our natural stone as it pointless in my opinion. Others may argue.

I have slabs of bluestone on my front portch. I had a very experienced landscaper install it and he does not recommend sealing bluestone as it is a very dense stone to begin with. He had a few clients apply a sealer to their bluestone, and it gave a slippery, and unsafe altered surface.

Mystic Pools - you don't seal them even with salt water pools?

We do not seal at all. We use a lot of Indiana Limestone for the coping and the patios and it is not recommended by the Limestone Institute to seal as it inhibits the stone's ability to "breathe" if you will.

And as @kculbers mentioned, the sealers can make the surfaces slick and that's not good around pool areas. Stamped concrete receives the same treatment and can have the same affect. We have not and never will use stamped concrete.

Honestly, in the 20 years or so since we have used salt water generators on our projects, we have not seen any degradation of any stone products, mortar or cement products.