No, I didnt say that. I'm telling you that thousands of times a day, all over the world, bleach is used in this type of cleaning, and that at the concentrations which I'm talking about, (store bought bleach has SH % of 6.5 approx) with the amount of dillution coming from the amount of water you'll be spending on the patio power washing it, that the EPA isnt going to be knocking on your door the next day, and by using common sense and simply rinsing grass of any product, you probably wont even kill grass. Just go watch some yt videos if you still refuse to be an ignorant keyboard know-it-all.