How is algae prevented?
Proper chemical balance and sanitizer residuals will prevent many opportunities for algae to bloom. high pH and low chlorine (or other sanitizer) can give algae a great start to genesis. General cleanliness of the pool is also important. Organic material and bacteria can contribute to algae growth. Regular brushing of seemingly clean pools is not only good exercise for you, but prevents dirt from harboring in the pores of the plaster, which is a good start for an algae colony.
The use of specialty chemicals or algaecides is recommended to provide a back up to normal sanitation and filtration processes and is completely necessary for many pools. These chemicals are described below:
This chemical, when added to the pool water in proper dosage, prevents algae from converting carbon dioxide into the fuel it needs for growth. Manufactured under the trade name Proteam Supreme. An extraordinary product.
Not an algaecide (meaning to kill algae) per se, but its properties might be called algaestatic (that is, to prevent algae growth). Chitin has the ability to coagulate and remove a wide variety of suspended materials and impurities from the water. This allows the sanitizer to more effectively kill contaminants unobstructed. It also improves the effectiveness of the filtration equipment. Sold under the trade name Sea-Klear, chitin can be a valuable weapon in your algae arsenal.
Algaecides and Algaestats:
Quaternary Ammonium Compounds:
A low grade type of algaecide, Quats, as they are called, will usually have "10" somewhere on the bottle, representing 10% active ingredient. 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. They are available in percentage strength of 30 - 60%, are non foaming, and work well as general, all around algae treatments. Poly-Quats are a blended compound of polymer and quats.
Copper is a proven algaecide and algaestat. Available in varying non foaming strength of 3 - 10%. It works very well on all types of algae, but it has the drawback of staining white plaster surfaces a light blue/green color if it precipitates out of solution. Most copper based algaecides are chelated, which means that agents have been added to prevent staining.
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.
These are not algaecides, but work to provide a synergistic boost to hypochlorites when added separately, but at the same time. Sold under trade names like Mustard Buster, Yellow-Out or Yellow Treat, it is most effective on, you guessed it, yellow algae. Since it is not an algaecide, the makers are not required to tell what it is made of, but we do know that it works quite well, in conjunction with a little brushing and vacuuming on your part.