Most of what I read about deck refinishing is incorrect. It is not necessary to introduce water during preparation for refinishing.
I recommend using a vibrating plate sander on the large flat areas and detail the edges where needed. DO NOT OVER SAND/POLISH WITH TOO FINE A GRADE OF PAPER! Most problems occur during this phase of the project.
We use 26 and 36 then final sand with no more than 50 grit. You are trying to open the grain of the wood and not impact it. Finally, use an air compressor or blower to get rid of the dust and then vacuum the deck to ensure a completely dust free surface.