|A very green pool laden with algae and sludge in the spring has probably undergone “nitrification” a micro-biological process that releases large amounts of nitrogen into the water. Poorly winterized pool water allows naturally occurring Nitrosomonas bacteria to decompose proteins from any plant life (leaves, etc.) and animal life (bugs etc.) that may have entered the water during the winter and spring. Ammonia and related nitrogen compounds are formed that further convert into nitrites and nitrates in an ongoing process called the “Nitrogen Cycle.” The bacteria feed on the newly created nitrates along with carbon dioxide in the water to grow and accelerate the cycle. As the water starts to warm in the spring, algae feeding on the same combination of nitrate and carbon dioxide grow rapidly. The result can be very dark green or black looking water.|
|From Years of experience with nitrification, a 5-10x normal
shock treatment is required to satisfy the
chlorine demand of the water and establish chlorine residual. These springtime episodes underscore a big problem associated with using EPA governed chlorinating shock treatments. Directions for use on shock treatment labels provide a minimum shock treatment dose between 5-10 ppm. That’s just enough chlorine to handle a light algae condition at best. Nuclo
Hit Hard and other Nuclo shock treatments are EPA registered to provide about 10 ppm of available chlorine, the high end of the scale.
Double or triple shock treatment doses, although not specifically listed on the label, have been used for many years to successfully handle medium to heavy algae conditions.
|Our industry would benefit greatly if the EPA would establish a minimum shock treatment dose and require all registrants and packagers to abide by that dose. Since this has not yet happened, pool operators and home owners are left to sort out a wise range of product strengths and a wide range of doses too.
Conclusion: If significant algae are present, use a 2x dose of a Nuclo
chlorinated shock treatment per application.