I wasn't exactly sure where to place this post, but, the white bricks around my rose garden have both what looks like algae, and water stains, and just misc stains from being outdoors.
I've tried soap and water with a little bleach, several types of my wife's house cleaning products, finally, muriatic acid, and a strong industrial cleaner from the local hardware store.
Nothing seems to work, and these bricks are not inexpensive, so I can hardly just go down and purchase new ones to replace these that don't look that great.
I didn't, and I'm not even sure what the concentration is; I'll check it out.
Actually, I found a rotary wire brush on a drill works well; also, it probably would be a bad ideal, but I could match the brick color and paint them.
I'd of thought the acid would have done it. Since acid doesn't clean them go the other way. I'd try mean green. I've used it to clean a lot of things that I couldn't get clean otherwise. It has a very high PH. If that doesn't work I'd try some lye based cleaner.
Thinking more on it If it has algae or moss growing on it it mush be shaded and damp. You may have to kill the algae, the bleach or acid should do that. Then clean it with something like mean green to remove the surface dirt and then use the acid to remove mineral deposits.
Have you checked with a brick and stone place? You can't be the only one in the area that has that brick and that problem.
Thanks for the replies. I'll check again and see if the acid works better at a certain concentration, but I honestly thought it was fairly dilute hydrochloric acid right out of the bottle, and didn't need any dilution.
Regarding stains, some of the stains are not only algae, but what looks like water rust stains (?); it didn't even touch that ! On the algae, bleach, comet, and dish washing detergent did a pretty good job. I didn't think of this before, but I'm sure a pressure washer would work really well.
I did try some of that cleaner that's used for hard water stains, but it didn't work out either.
Again, thanks for the info...a few more heads are almost always better than 1:) !
Hydrochloric acid should remove rust stains. I've used it to remove rust from steel. I suspect that you have multiple layers or grime. Some chemicals will remove one layer, but not another. If the layer it will remove is below the one it won't then it won't do much until you get the first layer off. Pressure washing might be the way to go.