Prevent algae before it becomes an issueThe addition of algicide is needed for proper pool maintenance. Sanitizers or shock/oxidizers alone may not keep algae at bay and this step is needed to keep your pool completely clear of any growth. This is the third part of the BioGuard 3-Step Pool Care System. Do all algicides kill algae?Not all algicides are alike, only algicides that have been approved by the EPA for killing algae actually perform. All BioGuard products have been thoroughly reviewed and proven effective. Various kinds of algae may require different treatments to ensure they are eliminated.