Are Salt Water Pools Really Better Than Chlorine Pools
Are salt water pools really any better than traditional chlorine swimming pools? This is something that every swimming pool professional has to deal with on a daily basis. People love salt water pools, or at least people love what they hear about salt water swimming pools. Whether the information is entirely true or not will depend on your sources. The harsh reality of the situation is that there is a shocking amount of misinformation out there in regards to salt water pools, how they work, and what benefits they can have for you, the pool owner. Starting at the top, a great deal of this misinformation rests squarely on the shoulders of unscrupulous or under-informed pool industry professionals trying hard to make a sale. You do not need to look very far to find a pool owner who was sold a salt water system based on the concept that it is basically "maintenance free" which it most definitely is not. You also do not need to look far to find a pool owner who makes the holy grail mistake of salt water pools by saying:
I have a salt water pool because I am allergic to chlorine
I am shaking my head "no" at you before you are finished saying the words. Collectively 10,000 swimming pool technicians around the world are saying into their computer screens in unison: "salt water pools are chlorine pools..."
While the majority of you reading this (hopefully) have read the last sentence and thought, "well, yeah...obviously" however there will be a percentage of readers who read that line twice and are wondering how (if) this can be true. It's true. I wish it could go without saying, however sadly it cannot, but salt water pools are chlorine pools. Instead of buying some chlorine that somebody else made from sodium chloride (salt) you instead bought some salt, and an electrolysis cell for generating your own chlorine. A salt water pool is not maintenance free, and it is not an alternative to chlorine in any way, shape or form. A salt system would perhaps be more aptly named as a chlorine generation system. In fact it is terminology at the heart of much of the misinformation about salt water pools.
Salt Water Pools - The first terminology that we should clear up is even the term "salt water pool" since, technically, you don't have a salt water pool. You have a regular pool with a sodium based chlorine generation system. Do you know what the difference is? If you put a killer whale into your pool he would die. Killer whales need salt water...and your swimming pool is a chlorine pool with a very small (relative to ocean water) concentration of salt in the water. A swimming pool with a salt system might be in the range of 3000 parts per million of salt, where as that whale is going to need closer to 25,000 parts per million of salt like ocean water is. So right off the bat calling your pool a salt water pool is incorrect unless it is actually fed with sea water.
Electronic Chlorine Generators (ECG)
Salt Water Generators (SWG)
Salt Chlorine Generators (SCG)
Salt Chlorinator Systems (SCS)
All of those terms refer to an electrolysis cell that separates the sodium from the chloride in order to generate free chlorine. When you choose a system like this for your swimming pool what you have done is changed the way that you add chlorine to your water, and nothing else. Every last bit of swimming pool water chemistry still needs to be monitored and maintained just the same as with any other pool, except that your chlorine is now delivered at the touch of a button (or turn of a dial) instead of manually pouring it into the pool. So if all of the same maintenance rules apply to the water chemistry then why do so many people think that salt water pools are easier to maintain or take less additional chemicals? The answer rests with the people selling salt systems to pool owners.
If a pool owner walks through the door already knowing that they want salt water then you would be doing a disservice to yourself to convince them that it is not as good as they have heard it to be. The end result is that often important conversations about limitations of salt chlorine technology are not had. Why risk spoiling the sale when the customer already knows what they want? The end result is that customers buy a salt system thinking that they are buying magic beans, and the (expensive) problems do not start showing up until much later in most cases. Things like metals stains in the pool, rusting of stainless steel surfaces, early failure of pumps and especially heaters...these are all very real concerns with any pool, but much more so with a pool that has an elevated salt level. If you would like more information about this subject you can check out this article about is salt water bad for pools?
Chemical Maintenance Of Salt Pools
Now you know that salt pools still require all of the same water chemistry and care as any other swimming pool, despite what you might have previously heard, so then why do so many of these salt pool owners get away with not taking better care of their pools? The answer is that they don't. Caring for a pool is very similar to caring for a car. Some people change the oil right when it is due, and some drive the car for another year until they get around to it. Some fix parts when they start to make noise, and others wait for the car to stop working before they investigate problems. Pools can be considered similar in that there is a spectrum of care that you can give to one, with a sliding scale of potential downsides and risk should you do a poor job of maintaining your water chemistry values.
Salt pools have the unique quality of always having a high pH. This is just a function of how salt water pools work, due to the pH of the chlorine that they generate being so high. There are different kinds of chlorine and they all have different pH ranges. If you use chlorine pucks with a very acidic pH then you would find that your water tends to have a lower pH value. When using a salt system you will need to work to prevent your pH from constantly being off the scale (8.4+) on the alkaline side. At high pH like that your chlorine is almost completely ineffective in the water, despite having a measurable reading, and so salt pool owners can get into trouble with unsafe or even green water despite having "enough" chlorine in the water. More commonly however is that the water has just enough active chlorine to not turn green, and so the pool owner (mistakenly) assumes that everything is good with the water. Not so.
Saturation Index - In the world of swimming pools we use the LSI (Langelier Saturation Index) in order to determine the "state" of the water. The water can be in an acidic state, a neutral state, or a scaling state. Can you guess which of those you want your pool water to be in? Salt pools, due to their chronically high pH, will almost all live in a perpetual state of scaling. This means the water is inclined to have scale formations on surfaces like your electrolysis cell, or the internals of your heater, or in a very bad case inside the plumbing lines and on the surface of the pool itself. Saturation index calculations exist because it is known that water outside of the neutral state is destructive. Failure to maintain your water in a neutral state will cause long term damage to many different parts of your pool, and if you have pH in the 8.2 to 8.4 range then you can be almost assured that your water is in a scaling state.
The real damage from using salt water and thinking your pool is "maintenance free" does not show up right away. It manifests slowly over time as early equipment failures and damage to your pool interior surface. Understanding that salt water pools are not maintenance free, but instead that they have unique care considerations, is key to protecting your swimming pool. If you would like more information about how to stop the pH from always being so high, and other tips unique to salt water pools, you can read this article about salt water pool maintenance.
What Makes Salt Water Pools Better?
Now that we are all on the same page in that salt pools are not maintenance free, and they certainly are not an alternative to chlorine, I am happy to start talking about some of the benefits to chlorine derived from salt water. First, who wants to handle bulk chlorine products? Unless you have a work truck buying and transporting chlorine is somewhere between a pain, and a serious liability. Buying a one-time huge order of salt (many hundreds of pounds) and then generating all the chlorine you need right inside of your pool is way more convenient. At most you will need to periodically add a bag or two of salt to make up for splash out or water consumed during backwashing or draining of the pool for service. By comparison it is clear that salt pools are better in this regard. Especially when you understand that you can still add chlorine to a salt water pool, should there be a benefit to you to do so, which sometimes there is. So it is nice to know you can buy and add chlorine if you need to, but largely you will not have to.
Water Conservation - Stabilized chlorine is chlorine that has cyanuric acid added to it. This helps the chlorine to be more UV stable but if you rely on only a chlorine source containing cyanuric acid you will eventually find that your CYA levels have climbed too high and you will need to partially drain and replace with fresh, untreated water. Salt water pools use a dosing of cyanuric acid to dial in the level to the correct range of 30 to 50 parts per million, after which this time you no longer need to add any more. So long as you avoid additional chlorine sources with CYA then your levels will remain fairly constant for long periods of time. If you live in an area where there are restrictions on water use then you definitely want to choose a chlorine system that does not require regular draining and filling, and salt chlorine generators are (arguably) a good solution in these areas.
Softer On Skin - This is a big one. Pools with 3000 parts per million of salt do feel different than a traditional chlorine pool that might be closer to 300 to 500 parts per million of salt as a byproduct of the chlorine that gets added to it. If the feeling of the water is a priority to you, then yes you are going to feel a (small) difference with how your skin feels. Establishing your priorities is the big variable that is unique to only you, and the reason why you can not really get good advice online about whether you should get salt or not for your pool. The priorities of someone else and their pool are almost certainly different than your priorities. People with skin conditions like eczema tend to really like salt water pools as an example of someone with a unique priority that alone could sway the decision to go with salt instead of traditional chlorine methods. you are also slightly more buoyant in a pool with 3000 parts per million of salt versus a lower value.
Chlorine Allergy - If you tell me that you like salt water pools because you are allergic to chlorine this is likely to elicit such a dramatic groan from me that I risk throwing out my back and being laid up for days. There is an exceedingly small percentage of people who have a confirmed allergic reaction to chlorine. If this is you, then a salt pool would probably kill you. Because it is a chlorine pool as we talked about earlier. Also, and I always ask this question, are you able to take a shower or bath in your home or do you have to use bottled (and dechlorinated) water to clean yourself. All municipal water supplies contain chlorine, and chloramines, so if you are allergic in your pool you will be allergic in the bath and shower as well. What is very common however is for some people to be very sensitive to pH, especially acidic pH, and pools often can be far more out of pH balance than you think. Since pH is measured on a logarithmic scale, a pH of 7.2 is ten times more acidic than a pH of 8.2. Further to this a pH of 6.2 would be 100 times as acidic as pool water at 8.2. It does not take a 100 fold increase in acidity for sensitive people to start having red, dry and itchy skin as well as red eyes. If this is your reaction you are likely sensitive to pH imbalance, and having a salt pool resolves this because your pH is almost certainly stuck above 8.0 where it should honestly never be.
Such has been the conversations for over 30 years. Salt chlorine generators are old technology and there are vastly more high tech solutions to maintaining high quality pool water, like advanced oxidation process systems for example, and yet pool owners still readily look towards the older salt chlorine technology for "chlorine free" and "maintenance free pools"...of which it is neither. If you want to know the reality of running a pool without chemicals then you should definitely read this article about chlorine free pools. If you have read all of this information and still like the sound of salt water, and you understand there are some small risks in adding 3000 parts per million of salt to your pool water and you are willing to take them because you want the convenience and benefits of salt water - then please do get it. An informed decision is one that you can be confident with and I hope that I have helped to arm you with the information you need to make this decision for yourself.
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