Take it from me that too much bleach will cause a chemical burn. I had a nasty one last summer. I have a large octagonal gazebo 16’X 24″ that my son got married in last Sept. Before giving it a fresh coat of paint I needed to removed the black mold that had covered the ceiling. First I power washed it as best I could, then I used the sprayer with a strong bleach and algaecide solution. Where I went wrong was ignoring a little pinhole leak in the sprayer. It constantly sprayed a little stream of the solution into my hand as I held it up pointing at the ceiling, which then ran down the length of the backside of my arm. By time I realized what had happened I had been burned badly. The wound was horrifying to look at, my arm got infected and was swollen so badly I couldn’t bend it, and it took months for the wound to heal. I wore long sleeve shirts for the rest of the season so that nobody would see my arm. A valuable lesson was learned.