Salt Water Systems - how do they work?
Salt water chlorine generator systems have become extremely popular in the swimming pool industry. However, many people (including some pool dealers) still do not understand how they work. We're going to cover some basics so you'll have a better idea of how they work.
Salt systems require two things to operate: salt (added to the pool water in the spring and once or twice over the summer) and the unit (which gets plumbed into your pool plumbing system). Once the machine is installed and the salt is at the right level, your machine will begin producing chlorine. That's right, salt systems produce chlorine. If anyone tells you differently, they need to brush up on their chemistry.
Salt is NaCl (sodium-chloride). The magic of the salt system is that the machine can separate the sodium from the chloride. At this point, through chemistry that I'm not going to cover here, the chloride turns into chlorine. Then the chlorine goes about its usual business killing algae and otherwise keeping your pool clean and clear. Once this process is done, the spent chlorine re-bonds with the sodium and the process starts over. This happens over and over and over again.
Important note: the salt level in the water doesn't directly affect the chlorine levels. If your salt reading is in the proper range, the salt system will produce chlorine. If your chlorine is low, check your salt level, if it's in the right range, DO NOT ADD MORE SALT, turn the output of the salt system UP instead, or have your water tested at your pool store.
Benefits of Salt Systems
There are several major benefits to salt systems:
- Cost savings - over the lifespan of an average salt system, the machine will pay for itself with chlorine savings
- Lower maintenance - with a salt system you won't have to add a weekly algaecide, fill your chlorinator with pucks, shock the pool, etc
- The water "feels" better - our skin and our eyes are happier in slightly salty water (sweat and tears are both salty) so we feel better in salt water pools
- No chlorine smell - The "chlorine" smell that people complain about is not actually caused by chlorine. It is caused by what's left over after chlorine disposes of something. The best way to get rid of these smelly things is lots more chlorine. The salt system is constantly producing high levels of chlorine inside itself, which constantly removes the smelly things from the water. This is why a lot of people think (incorrectly) that a salt water pool is chlorine-free!
Cons to a Salt System
- Salt systems don't work when the water is cold, so early and late in the season you will need to manually add chlorine to the pool
- Salt makes the pool water more conductive, which can increase the level of galvanic corrosion (rusting ladders, etc) if your pool was not properly grounded when it was built (this is a common problem in my area)
- Salt is corrosive - leftover salt residue can cause corrosion and pitting of stone, concrete and steel. We recommend that salt systems and softer natural stone should not be installed together. We have not seen evidence that salt water pools with sealed stamped concrete patios are a major concern, but ask your concrete installer.
In conclusion, we have installed many salt systems in the last 10-15 years. The vast majority of those customers love their salt systems. They are a low maintenance and low cost (over the long term). Let us know if you have any questions in the comments.