We are seeing chlorine resistant algae this swimming pool season. This happens when a pool that has residual chlorine is let to sit without flow over the course of the winter or a very low amount of chlorine was used to sanitize the pool with very little flow. It often results in a swamp of different strands of algae who have become tolerant to the sanitizer normally used.
Nearly every pool owner has had to deal with algae problems at one time or another. Even with a properly-working filtration system, sanitizers at their recommended levels, and a watchful eye, algae blooms can still develop. Algae spores can enter a pool in a variety of different ways, but is most commonly introduced into a pool through wind, rain, dirt, and even on a swimmer’s body or bathing suit. Keeping algae spores out of your pool is impossible, so it is important to prevent the microscopic spores from turning into unsightly algae blooms. Maintaining clean, algae-free water will help keep your pool and your family happy and healthy, and we're here to help prevent and protect your pool from any algae problems!
Here's a link to an article that helps explain how to prevent algae growth in your pool: http://www.lesliespool.com/blog/pool-care/pool-algae/top-10-algae-prevention-tips/