The concrete walk in front of our house doesn’t get a lot of sun, and as a result it has slowly turned green from algae growth. It didn’t smell funny or feel slippery or anything, but man it bugged me having green stains on the walkway.
So I did some research!
I guess the traditional way of cleaning algae or mold off of a sidewalk is to rent a powerwasher for a day and just spray it off. However some people say that repeated sprayings will actually damage concrete! And renting or buying a powerwasher would have been expensive.
So I did some more research!
There was a simple chemical solution to my problems! You’re thinking bleach, probably. So was I! But no! Pool chlorine is actually much stronger than say, Clorox bleach. There’s even another pool chemical called “shock” which is basically super concentrated (x10) pool chlorine that you’d use to clean up your pool in a hurry if you let the chlorine level get too low.
So I got a small brush with a four foot handle and a bottle of granulated pool shock at Home Depot a little while ago and went to work! At first I tried putting some shock in a bucket and adding water, then dipping the brush in and scrubbing away at the algae. That worked, but not very well.
Finally I just sprinkled the shock all over the walkway, sprayed it lightly with water to get it moist, let it sit for about ten minutes, then scrubbed it lightly with the brush. Two applications later and the concrete walk looked like a concrete walk!
I was really happy! For about six hours! Then the burning and the rashes began.
I thought I was really good about keeping the liquid off of my hands when I was working, but apparently I wasn’t good enough. Shortly after finishing I noticed itchy rashes and some small bumps starting to appear on my hands. The moral of this story is to wear gloves when working with super powerful chemicals, because even if they don’t hurt you right away they’ll come back to haunt you later!