If you're considering a change in your pool’s chlorination system, calcium hypochlorite (cal hypo) tablet chlorination systems are a common alternative. But educating yourself on the basics of these systems is a smart idea before making a purchase.Feeders 101
Chlorinator feeder systems are not complex, but ones that are well-designed and manufactured can lead to great results for your facility’s water quality. In short, incoming untreated water enters the chlorinator drum from a side stream. The tablets are placed in the chlorinator on top of a screen or sieve plate and as the side stream of untreated water rises, water flows through the holes of the screen to make contact with the bottom of the tablets. Since the water only contacts the tablets at the bottom of the feeder, the tablets on top remain dry. As a result, the tablets don't dissolve prematurely. The treated water—known as chlorinator effluent—is returned to the main system flow, providing the desired level of available chlorine to meet the facility’s needs.
What Are Cal Hypo Tablets?
According to White’s Handbook of Chlorination and Alternative Disinfectants, calcium hypochlorite is available in a variety of forms, including powder, granules, briquettes and tablets. Dry calcium hypochlorite is the most commonly used form of dry bleach in North America. Cal hypo tablets contain 65 percent chlorine compared to liquid bleach, which has only 12 percent. The calcium component is less corrosive and prevents damage to concrete, plaster and piping in the pool.
While all cal hypo tablets perform similar functions, results will not always be the same depending on the manufacturer and chemical components. Understanding the differences between reliable and unreliable tablets is essential to producing the best and safest results.
Making the Change
If you're considering changing your facility to a calcium hypochlorite system, there are some important things to make note of before purchasing. Make sure to choose a supplier whose system has undergone rigorous industry testing. NSF/ANSI 50 is the gold standard as far as testing goes. By visiting the NSF/ANSI 50 website, users can search "Flow Through Chemical Feeding Equipment" to see which manufacturers have undergone this testing. Mixing incompatible chemicals—including other pool cleaning chemicals—may generate heat, release hazardous gases and potentially cause a violent reaction leading to fire or explosion. Additionally, tablets from different labeled buckets should never be mixed.
Calcium hypochlorite systems can make pool chlorination and water treatment much simpler, but it's important to educate both yourself and your staff before purchasing one for your facility.