Salt Water Pools Are Not Without Cons and Disadvantages: Scale
17 Jun Salt Water Pools Are Not Without Cons and Disadvantages: Scale
Posted at 13:25h in General Interest
Scale Problems In Saltwater Pools
Saltwater pools have been presented to an unwitting public as a panacea: they are maintenance free. Additionally, some more unsavory pool professionals have actually sold these Electronic Chlorine Generating systems as Chlorine free. The public is finally coming around to realize that salt water electronic chlorine generation systems are not everything they have been cracked up to be. Saline pools do have some real benefits, but there are also some serious issues associated with them that can shorten and damage the life expectancy of major pool equipment and materials. This post from Aqua explores one of the most common issues associated with these systems, the formation of scale.
Here is an excerpt from the post:
ver find little white flakes on the bottom of the pool near the return? These are little pieces of calcium carbonate that have broken off and traveled through the system. If it’s a saltwater pool, they very likely came from the electrolytic chlorine generator (ECG). They formed around the blades or plates in the ECG and then chipped off, and were swept through the piping and into the pool. They may seem like a minor irritation, but mineral deposits are the No. 1 enemy of salt chlorine generators.
Finding scale in pools is nothing new; we’ve seen it from the beginning of the industry. Almost any vessel that contains water, whether it’s a pool, spa, boiler, hot water heater or even a saucepan, will become encrusted with minerals at some point, but the problem takes on a special significance in pools with salt chlorine generators.
Scale is one of the most common and serious challenges in saltwater pool maintenance, partly because it typically forms first on the cell plates inside the ECG where it can remain undetected until the problem is well advanced. Once it has formed, it hampers the effectiveness and life span of the ECG, which wastes the customer’s money and can lead to premature replacement.
Salt chlorine generators, by their nature, create ideal conditions for the formation of scale, and despite the efforts of engineers to design these systems to prevent the scourge, it continues to cause damage and early failure in ECGs on a wide . . . scale.
The history of scale is as old as hot, hard water; assuming the laws of chemistry have been evenly enforced throughout the ages, scale must have coated the cooking pots of Roman legions and been an annoyance to Nebuchadnezzar’s chef.
Scale is simply the term for minerals falling out of solution and forming mineral deposits. Calcium is the mineral with which most people are familiar, but other ones common in pools are phosphates, silicates and sulfates.
It’s a natural, and to some extent, an inevitable process. It has become a greater concern in recent years, however, due to the fact that it degrades the growing number of chlorine generators.
Before salt systems became popular, the pool heater was the most likely location for scale to form in any pool system, because it’s hot there, and scale loves heat. But since then we’ve added a rival for scale’s clinging affection — the ECG. It’s hot, too, and it has the added attraction of an enticing chemical environment of extremely high pH.
That high pH is a result of the chlorine production process, says Zach Hansen, technical services engineer, BioLab, Marietta, Ga.
“The generator is converting the salt, sodium chloride (NaCl), into chlorine for the pool and a by-product of that process is sodium hydroxide (NaOH), which drives the pH up,” he says. “And that creates conditions very favorable for the formation of scale in the cell.”
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