Sold under the trade name Sea-Klear, chitin can be a valuable weapon in your algae arsenal. Although available at a lower cost, quats tend to produce a small amount of surface foaming. They are most effective as an algaestat, that is, as a prevention, not a cure. Polymers are long, complicated chemical chains that behave in water both as an algaestat and an algaecide. Poly-Quats are a blended compound of polymer and quats.
Copper is a proven algaecide and algaestat.
Most copper based algaecides are chelated, which means that agents have been added to prevent this, such as Lo-Chlor Algaecide. Silver has been shown to be an effective bacteriostat, which means that it works to prevent bacteria from reproducing. Non foaming and effective with pink algae. In high doses, reactions with sunlight can cause colloidal silver to deposit as black stains on white plaster. When using copper or silver algaecides, the use of a sequestering agent is recommended.