Tips on cleaning exposed aggregate patio?

Hi all! I have a job coming up consisting of exposed aggregate sidewalk and patio. This will be the first time i’ve ever cleaned anything like this. It’s about 1200 sq. feet total. It looks like it’s been neglected for several years. It’s dark and dirty looking in spots and green with mold in many places. I have a 4gm/4000psi machine with a surface washer that I was going to use on it.

can I just downstream an sh mix, let it dwell and then surface wash it? how much pressure should I use?

Do you guys try to up-sell a sealer application on a job like this, and if so, what do you use and how much?

Any info would be much appreciated.

I would use a pump sprayer or 12 volt if you have it and use a little stronger mix if it is real dirty. Then just clean as normal. Let the mix dwell a little bit. You might have to hit it a couple times.

when you say “clean as normal” do you mean with a surface washer? i’m a total noob, so i don’t know what normal is on exposed aggregate.

Yep. You should be fine with the surface cleaner.

will sodium hypochlorite do damage if after it’s dried is rinsed into any gardens? If so, what can be used that is safe with surrounding gardens, please?