Conversion to Salt
The title of this post is actually a bit of a misnomer. Conversion is a word that people commonly use when discussing the addition of salt to their swimming pool. The only conversion that happens though, is the conversion of the salt into hypochlorous acid and then back to salt again. Before we get any deeper into the way a salt chlorinator works, it is important to understand what it actually consists of.
Salt System Components
A salt chlorinator, commonly referred to as a “salt system” consists of a few components that work together to sanitize your pool water.
There is the “salt cell” that handles the physical production of chlorine. These cells mount inline on the plumbing. Water flows through the cell and electrolysis occurring within the cell produces the desired hypochlorous acid. The cell itself is “dumb” and is either switched on or off. This is where the next component come into play.
Since the salt cell produces chlorine at 100% or 0%, we need a way to regulate it so that the desired amount can be obtained. This amount will vary depending on pool size, surroundings, and swimmer load. The control box allows us to adjust the amount of chlorine being produced. In most cases, it switches the cell on and off as needed to create the amount of chlorine desired. For example, if set at 50%, the cell will operate at 100% for 10 minutes and then 0% for 10 minutes. A few cells, such as Pentair’s IntelliChlor, have the controls mounted on the cell itself. Personally, I think it makes more sense to keep the controls separate from the cell so that you don’t have to replace both if one of the two should fail.
The other critical component to any salt system is a flow sensor. If a salt cell were to produce hypochlorous acid while water was not flowing through it, there would be major problems. Hydrogen is released when the chlorine is created and this would create a gassy buildup in the plumbing. The chlorine being created could also backup into a heater or other equipment under a no flow condition and this would cause damage over time.
The flow sensors vary between salt systems. Hayward and Pentair use a mechanical sensor where two strips of metal make contact when water is flowing. Jandy uses a strange combination of temperature sensors to determine if there is flow. Either way, these sensors are replaceable with most salt systems.
Now that the components have been identified, you may have noticed that these are all additional parts and not similar to your existing pump and filter. Many people think that the salt goes into a filter or that the filter will be replaced with a “salt filter”. This is not the case at all. The components discussed above are added to your existing equipment and the salt is added to the pool water just like any other chemical. There are a few catches to salt system installation and proper maintenance afterward. Sometimes there can be extreme corrosion issues if the pool is improperly bonded. Removable deck railings can become stuck, lights can rust, cloudiness can occur from microscopic hydrogen bubbles. Salt systems are incompatible with stainless steel filter tanks. There are a variety of things to check out before installing a salt system, so it is always best to let a professional look at the equipment before diving in head first.
If you would like some additional material to read, have a look at this previous post for some frequent questions and answers about salt systems.