What are the risks of using bleach to clean algae from marble outdoor planters?

Using bleach to clean algae from marble outdoor planters may seem effective, but it poses several risks. Marble is a porous, delicate material, and bleach can cause discoloration, etching, or permanent damage to its surface. The harsh chemicals in bleach can strip away the natural shine and weaken the stone over time. Additionally, bleach runoff may harm nearby plants or soil. For safer alternatives, consider using mild soap, vinegar solutions, or specialized stone cleaners. Always test any cleaning method on a small, hidden area first to avoid unintended damage. Regular maintenance and gentle cleaning can preserve the beauty of marble planters without risking harm.