Black Algae: Can You Accidentally Infect Another Pool?
Black algae in a swimming pool is one of those problems that feels personal because it fights back. The spots look like tiny black pinheads on plaster, but the real issue is what’s underneath. As the podcast explains, “black algae” is often cyanobacteria, not true algae, and it can anchor itself deep into porous surfaces. That helps explain why it returns when chlorine drops, and why simple “shock it and forget it” pool maintenance fails. If you’re a pool owner or a pool service professional, the goal is twofold: kill what you see and prevent black algae from spreading to the next pool through cross contamination. A key takeaway is how black algae spores can enter water in the first place. The idea that it comes from nature, including oceans and lakes, is plausible because spores can cling to wet fabric and damp gear for surprisingly long periods. A wet bathing suit, towel, or T-shirt can carry spores from a beach day right into a backyard pool. The same is true for pool cleaning tools...