Bio-Dex Skill-it is a very effective and powerful algae remover. It eliminates and controls multiple resistant forms and colors, as well as the most persistent algae. Bio-Dex Skill-it does not require pH adjustment. It even helps keep pesky insects away, such as bees and wasps. Skill-it contains no heavy metals, is non-metallic and non-staining. It's a great compliment to most swimming pool sanitizers.