What sort of timber are you using ? We used Merbau/Kwila on our deck and after a fair bit of consultation with a couple of helpful board members I finally took the step of cleaning and staining/coating the deck on the weekend using Spa-N-Deck.

Lots of helpful posts including different colours available in this thread :
http://www.woodworkforums.ubeaut.com...ad.php?t=49270

My results here : http://www.woodworkforums.ubeaut.com...t=49270&page=4

The main part of it is the cleaning. I used a Karcher to get the mud and crap off (i'd left it for almost 3 months before doing it), then used Flood Powerlift, used a scrubbing brush and scrubbed, left for 20mins then hosed it off. Followed by the Flood Prep, scrubbed it in, left it for 20 mins and then hosed it off. Then came the 3 coats of Flood Spa-N-Deck Cedar.