Blackspot is notoriously difficult to remove due to its hard black 'shell' which doesn't scrub off easily which protects the algae underneath. However, removing it isn't as difficult as it sounds.
Green water or algae on the walls is generally a sign of low chlorine, however, it is usually accompanied by a high level of phosphate in the water as well… So what is phosphate and how do you get rid of it?
Pool water turns green because of algae in the water. Algae can grow rapidly, particularly when it’s warm like summer, which is why it can surprise you overnight.
