I have a product called "Techni-Seal WP" that I will be applying in a few weeks to my pavers. The instructions suggest you wash the pavers (degreaser/cleaner and/or efforescence cleaner) before sealing as you will seal in any dirt or stains. My neighbor already did his pool deck and he used a sponge roller (like a paint roller). This is how I plan to apply as well. The problem with the sprayer is over spray. The roller puts the sealer were you want it. You can pressure wash but use a wide pattern so you have a lower pressure (a pressure you would be comfortable washing your car with). I am also refilling my missing sand with a sand called "Polymeric Sand" also by Techni-Seal (other companies sell this too). This sand, once wetted dries hard so it won't wash out and grass and ants can't come through.
Good luck and enjoy your pool.