Technical Advice

Algaecides: Many Cures


Alden Leeds, Inc.

Manufacturer of chemicals that care for your pool


Technical Document #3




Algae are constantly infecting water through airborne contact which is accelerated by rain and wind. If algae spores are killed off as they enter the water by using repeated algaestatic or maintenance doses of algaecides, the incidents of alga bloom are effectively eliminated. This is an "insurance policy" approach compared to the cost of treating alga bloom.


If algae does bloom (become visible), then the best approach is to adjust the pH= 7.2-7.8, shock treat the water with 7-10 ppm of available chlorine, brush all surfaces vigorously, and follow with a killing dose (5x maintenance dose) of algaecide. Continue to filter and backwash, if necessary, during the entire episode.


According to the United States EPA (Environmental Protection Agency) all approved algaecides prevent and kill most strains of algae. There is no rule or clear-cut order to determine which algaecide to use, so choosing algaecides is similar to choosing medicines. Start with your favored choice and proceed from there. If algae persists, try another choice.


Here are the algaecide choices and their characteristics:


QUAT TYPE - This is the nickname for Quaternary ammonium chloride. It is economical, long-lasting, non-staining (non-metallic), excellent wetting properties (penetrates microsc- opic cracks). Will foam if overdosed. Best used for floating green, clinging green and pink algae.


POLYMER TYPE - This is the nickname for an organic polymer. It is fairly expensive, very long lasting, non-staining, and non-foaming. Manufacturer data suggests it is more stable in the presence of high chlorine than "quats." Best used for black (Dark green complex) and pink algae.


COPPER TYPE - This is a chelated (controlled) copper solution. It is very economical, very long lasting, and non foaming. Can cause blue staining or "green" hair. Best used for floating green and mustard algae.


SILVER TYPE - This is a silver colloid (controlled) solution. It is very expensive, short lived (curative use only), and non foaming. Can cause brown staining if mis-handled. Best used for black and mustard algae.


All other approved algaecides are dilutions or blends of these four types.

©2012  Alden Leeds, Inc.