I dont do a lot of pressure washing but I was doing 3 houses back to back 2 weeks ago, and when I got there(by myself) there were 3 guys right across the street doing this one house. So I unload the 8hp Honda powered pressure washer I rented from Home Depot, and went to start the pretreatment with bleach by dropping the included soap hose into the bleach bottle, then I turned it on and climbed up to the top of the garage to do the 2nd floor siding over the garage. In the mean time, the guys across the street had already started. So I quickly discover that the soap hose isnt working, and isnt sucking out any bleach, so I unhook it. Then I grab my 4 gallon backpack sprayer, clean it out, and mix about 2 gal of bleach with 2 gallons of water, then I go and soak the siding with bleach. While I'm doing it, I can see all the dark green and brown dirt and moss just disappearing from the siding! So after soaking with bleach, I turn on the pressure washer, but by that time, all I had to do was just rinse it off cause the bleach had done all the work! So I had to do the 1st and 2nd floor sides on 3 houses, and yet I got done doing all 3 houses by the time the other guys across the street finished doing that 1 house! It wasnt because I'm the world's best pressure washing guy or anything, it was because I pretreated my 3 houses with industrial bleach mixed with water, which actually ended up doing 95% of the work for me! But the 3 other guys werent using bleach, so they had to spend all this time slowly running the wand over each little area while holding the nozzle only about 4" away from the siding. Now, bleach works real good for siding, but now I've gotta do 2 decks at those same houses, then I gotta seal them with clear, 4 year sealant. But bleach isnt the right chemical for that job, and I dont what is...... There's something else that is supposed to be used on wood decks to clean them, and I believe there's even another chemical that will actually draw out the old stain from the deck surface. I dont think I need that, as the decks arent stained with dark stain or paint, and I think they have just been repeatedly sealed with clear sealant, so thats what I need to use after they are cleaned. But whats the chemical that I'm supposed to use on decks to help clean them?