There are many different types and strengths of swimming pool algaecides, however we will talk about two of the main components found in most algaecides, how they work, and the difference between the two.
These types of algaecides are strong chelating agents that help to break down the cell wall of the algae. Polyquats are highly effective against the more resistant forms of Mustard and Black algae. This type of algaecide kills and controls the growth of algae and microorganisms by disturbing their normal metabolic process of the living cell. Positive charged polymer attaches itself to the algae or bacteria cell walls and blocks the inflow and outflow of nutrients and waste causing cell death within hours. Polyquats basically kill and prevent algae by suffocation. Mustard and Black algae have a much harder shell that has to be attacked in order to allow it to be penetrated in order for the algae to be killed.
Poly Quat algaecides do not contain any metals and are usually in concentration from 30%-60%. This type of algaecide also does not foam.
Copper based Algaecides
A copper based algaecide is a heavy metal, liquid algaecide, fungicide, and bactericide. Copper products are both algaecide and algaestat. This is one of the most popular algaecides used and it is very effective on all types of algae. Copper algaecides lasts longer than Polyquat algaecides, usually up to several weeks longer depending on water pH. The toxic action of copper is attributed to its ability to denature cellular proteins and to deactivate enzyme systems in fungi and algae. Copper especially poisons algae. A copper algaecide is a lower cost option that is most effective for green and black type algae. The only disadvantages of this type of algaecide are: pH sensitive and stain potential with pH above 8.0.
Please keep in mind that there is a huge quality difference between many different chemical manufactures. We always recommend staying with a professional line of chemicals for your swimming pool, which will have the least amount of fillers and the highest amount of potency.