Pool School: Salt versus Chlorine
If you’re planning on diving into a backyard pool project this summer, there may be more options than you think.
For starters, traditional chlorine purification is no longer the only choice. Steve Terry, President and COO of California Pools, Inc., in the southwestern US, estimates that 75% of new pool installations use a salt system, and naturally-filtered pools are now available, too.
Pass the salt, please
A salt swimming pool is not the same as seawater. “Some people think you’re going to taste it, and it’s going to be like swimming in the ocean, but it’s not,” says Terry. The salt concentration of seawater is 40,000 parts per million, but in a salt pool it’s just 3,000. “A salt pool is a chlorine pool, but it uses electrolysis to convert sodium chloride into chlorine, as opposed to pouring chlorine into a pool,” he explains.
Salt pools reduce the amount of chlorine in the water. Their main benefit is the way the water feels. “Swimmers emerge with soft skin and hair, and people will open their eyes under water,” says Dale Dowdell, sales manager with Dolphin Fiberglass Pools in Trenton, Ontario.
“The bacteria in the pool eats up the chlorine and converts it [back] into salt. If you had the proper [salt content], theoretically you’d never have to clean your pool again,” Dowdell says. He estimates a cost of about $2,000 to convert a standard chlorine system to salt, which represents a modest increase over the total cost. “You can spend anything from $7,000 for an above-ground pool, to a granite pool that could be in the hundreds of thousands.”
Terry estimates that “$50,000 to $75,000 is going to be the cost of your average American backyard swimming pool. You’re introducing another $1,500 to $2,200 for salt.” But salt pools are less expensive to maintain. Compared to chlorine, salt (priced at under $10 a bag for only a few bags a year) is economical.
About five to seven years after installation, two parts of the system will likely need to be replaced: the filter cartridge and the cell where the electrolysis occurs. Each costs roughly $600.
Salt systems do have some disadvantages. They are not as effective in cool temperatures, the salt can damage porous rocks located nearby and it may slowly cause corrosion to metallic elements like deck ladder anchors.
Like any swimming pool, salt pools require routine maintenance, which includes regular cleaning, occasional measures to keep the chemical components of the water in balance, and shut-down and start-up for months when the pool is not used.
Another very exciting development in home pools is the naturally-filtered pool that uses planted areas around the pool’s edges to clean the water. In a system that’s working perfectly, the water can even be potable. It works by drawing water through filtering stones to trap larger debris. Beneficial bacteria then break the organic matter down into food for the plants.
Nicholas Bott, and his wife Catherine Neville, founded The Pond Clinic Water Garden Centre in Ottawa, Ontario, which only installs natural pools. “The biggest benefit of a natural pool is the landscape, so in those parts of the season when it’s too cool to swim, you can still enjoy your swimming pond from a decorative viewpoint,” he says. The pool can be designed to almost any shape.
“Even if you’re not swimming, you have the advantage of having a natural water feature on your property,” says Jean-Marc Daigle, president of Genus Loci Ecological Landscaping in King City, Ontario. Ironically, this is the biggest obstacle for some potential owners. “For a lot of people, it becomes a deal-breaker when they realize they will be swimming in an ecosystem,” Daigle says.
Water-loving insects will land on or skate across the surface of the pool. “We had a client who had a problem with a snapping turtle coming to their pool from a nearby pond,” Daigle says. Cottagers on lakes and rivers face the same problems. More significant is price point, which Bott estimates to be about twice the cost of traditional pool systems.
Naturally filtered ponds or pools do require some maintenance. For starters, the temperature must be carefully controlled. Because of the large water area, natural pools are expensive to heat, a disadvantage for people in northern climates. Conversely, people in hotter places may have trouble with pathogens multiplying in warm water; a UV sterilizer can help in these cases. If the owner has a high tolerance for sediment and algae, they can clean the pool less frequently. However, beneficial bacteria must be added regularly, skimmers must be maintained and it is common to drain and flush the pool over the off-season.
Whatever your style, with so many options, there’s sure to be a perfect pool for you. If you’re thinking of taking the plunge, be sure to ask plenty of questions to make sure you choose a pool you can live with – and love.