For horizontal surfaces (your deck), use a squeegee to remove the pools of water from the deck surface. If the pools remain on the deck and dry, it is likely some dirt will remain. The built-in squeegee on the back of the Cabot's Deck Prepbrush is perfect for removing pools of water from the surface of your deck.
We would not recommend using Cabot's Deck Clean for removing this dust. Cabot's Deck Clean is Oxalic acid based and is specially designed to prepare your deck for oiling or staining.