Sanitize, Don't Agonize
By Debra Wood
With the push of a button or flick of a switch, automated systems allow pool and spa owners to remotely control virtually everything from the lights to temperature.
And when it comes to the chemical conundrum that ensures water is safe, soft and clean, high technology breakthroughs provide for fingertip ease -- without having to use your digits to call a service technician.
Just set the perimeters on an automated sanitizing system, and forget it: The pool equipment takes care of itself.
Although homeowners must still monitor pH and take steps to rid water of dirt, oil and other unwanted elements, these systems save time and effort, helping you enjoy silky smooth water with fewer chlorine highs and lows that lead to red eyes, irritated skin or algae blooms. Several types of products and technologies exist.
Salt Chlorine Generators
These systems, which are popular for inground pools -- and sometimes can be used for aboveground pools -- produce a steady amount of chlorine to keep algae and bacteria in check, and help give water a smooth, silky feel. They are often integrated with automatic control units, allowing you to monitor the system from indoors. Electrolytic chlorine generators convert sodium chloride, or salt, into chlorine. The salt water passes over a catalytic cell, plumbed into the circulation system. Plates in the cell convert sodium chloride ions into an effective sanitizer.
With these systems, you don't have to handle chlorine (but you still have to check water balance and add stabilizer and salt, available in 50-lb. bags). Chlorine generators require a fairly constant salt level, around 3,000 ppm. In rainy climates, such as Florida, expect to add salt more frequently than in a more arid environment. Pool owners must also routinely inspect and clean the cell, removing scale, a crusty deposit that forms on the plates. Some units come with an electronic display that tracks salt levels.
Prices depend on the size of the pool and the unit's features, such as reverse cell cleaning or super-chlorination options. Reverse cell cleaning decreases the frequency of manual cell cleaning. Super-chlorination allows the homeowner to shock or oxidize the pool water at a touch of a button. Salt chlorine generators range in price from about $600 to $1,850, plus installation.
Ozone Systems
These systems infuse the water with ozone, an active form of oxygen that acts as a sanitizer and oxidizer to remove unwanted elements, such as oil or organic substances from water. Ozone dissipates quickly and does not leave a residual; therefore, it must be used with a sanitizer.
Combination salt chlorine generator-ozone units are available and offer the ultimate in sanitizing and oxidizing. The chlorine generator ensures a steady level of sanitizer, and the ozone helps clarify the water and eliminate calcium and other metals that may enter the water through the chlorine generation process.
Two methods -- corona discharge and ultraviolet -- allow the splitting of oxygen molecules to produce ozone. Corona discharge units use an electrical charge to generate large amounts of ozone. The electrodes should last about 15,000 hours. A lamp bulb in the ultraviolet systems causes the release of ozone. The bulb must be checked periodically and replaced after about 9,000 hours. Prices for ozone systems depend on the size of the pool, and typically range from $200 to $1,200 uninstalled.
Mineral Systems
Mineral systems are used in conjunction with a low level of chlorine or bromine to maintain a steady amount of sanitizer residual. They do not oxidize, however, so a periodic chlorine or monopersulfate shock is needed.
In these systems, a mineral cartridge is fitted into in-line equipment or into the center of a cartridge filter in pools; in-line or floating devices are available for spas. Depending on the product, these cartridges release silver, copper or other metal ions to destroy bacteria and algae; they last about six months and cost about $100 to replace.
Ionizers use an electrolytic process that produces copper and silver ions as water passes through internal copper and silver bars. The devices range in price from about $270 for an aboveground model to $700 for an inground pool of up to 75,000 gallons.
Chemical Feeders
In-line feeders present one of the more low-tech options for helping to maintain stabilizer levels. Rather than placing chlorine or bromine pucks in a floating device, you drop them in a feeder piped into the plumbing system. When the pump is on, water flows past the feeder, the tablets dissolve, and chlorine or bromine is dispersed into the pool. Homeowners can adjust the flow. In-line chlorinators cost between $55 and $75 uninstalled; in-line feeders combining chlorine tablets and mineral cartridges cost about $450.
Biguanide systems have become even easier with automatic dosing systems to control and adjust the amount of sanitizer, oxidizer and algicide added to the pool. (Biguanide is a nonchlorine sanitizer and is not compatible with chlorine.) With hot tubs, a dispensing system automatically releases the proper amount of biguanide based on the biweekly sanitizer test strip results. If you forget, the unit will default to the lowest setting and continue to sanitize.
Erosion feeders offer a reliable, long-lasting method of delivering chlorine or bromine to pools safely. These low-tech devices are plumbed into the circulation system. Solid sanitizer is added to the unit, and as the water passes through the feeder, the pucks or sticks dissolve, and the sanitizer enters the water.
A dial lets homeowners determine the output by limiting or slowing down the amount of water passing through the feeder. The best feeders are those where the water does not fill the unit so it is truly eroding the sanitizer from the bottom. This type can better meter a small amount of chlorine, such as the little bit needed with a mineral system.