Swimming pool saltwater system trade-offs

Saltwater systems are very popular right now. There are pro’s and con’s. I want to briefly cover both sides in an effort to provide those considering upgrading or undergoing a serious saltwater system repair some objective information on both the case for and against a saltwater system.

I would like to point out that a saltwater pool is still utilizing chlorine to sanitize and disinfect the water. The salt cell for a saltwater pool is basically a chlorine generator creating chlorine through the process of electrolosys. See one of my earlier posts if you are interested in how a saltwater pool or salt system works.

Chlorine gets a bum rap in our industry sometimes… however it is my opinion that a lot of the bad perceptions generally held by the public about chlorine are due to less than optimal maintenance.

The Pro’s:
Those who are fans of saltwater swimming pool systems will stress the benefits of:

1.) Smoother feeling water. Many argue that the chlorine doesn’t feel as harsh and is easier on the eyes and skin.

2.) Greener Pool. The good kind of green. The arguement is that a saltwater swimming pool is a more “natural” or green alternative to the traditional forms of chlorine.

3.) That a saltwater pool is cheaper and/or easier to maintain. I have had a number of customers tell me they were told “All I have to do is add salt and the pool will take care of itself.”

I believe items #1 and #2 above both have merit but know for certain that #3 is false. A saltwater system definitely costs more up front than an in-line chlorinating system and even a top of the line ozonator combined. So there is definitely more up front cost. There is also the issue of maintenance. Instead of the typical forms of chlorine a saltwater swimming pool will need more sodium bi-carb, more acid, and more cyanuric acid or chlorine stabilizer than a regular chlorine pool. The costs of these additional items often often slightly exceed the costs of using straight chlorine.

It is true that the pool water in a saltwater system can feel smoother to the skin and it will more closely match the saline levels of salt in a bather’s eyes. However probably one of the largest reasons the water “feels” better is due to continuous chloramine oxidation. Oxidation is the process of chlorine breaking down particles or debris in the water to smaller pieces. This process is the cause of about 90% of the chlorine used in many swimming pools. If a pool loses less chlorine due to oxidation then the chlorine can be maintained at a lower level on an ongoing basis.

As chlorine is used up it leaves behind chloramines. Chloramines are the by-product of chlorine oxidation that hurt bather’s eyes, smell bad, and feel harsh on their skin. Chloramine creation can be reduced significantly with the help of either a saltwater system or an ozonator carrying out a lot of the oxidation in the water. The traditional means of oxidation is shock or superchlorination. Superchlorination is achieved when the free chlorine in the pool water is 10 times the amount of chloramines. So for example, if you had 1ppm of chloramines you would need to get the free chlorine in the water above 10ppm to be strong enough to oxidize the chloramines.

When the water passes through the saltwater system’s salt cell (or chlorine generating cell) the cell itself creats a large amount of chlorine. This large amount of chorline in the plumbing immediately after the salt cell actually can achieve superchlorination and oxidize the chloramines that are going through the plumbing.

Con’s:
As someone who overseas hundreds of pools on a daily basis I can tell you there are some con’s.

1.) More maintenance. There are just more parts in motion as far as chemistry goes… or at least several of the chemical items move faster with a saltwater system causing more balancing and a lot more volume of stuff to be added on an ongoing basis.

It starts with the pH. The pH rises as electolosys occurs on a daily basis. This requires more muriatic acid to bring the pH back down. When the acid is added it pulls the total alkalinity (TA) down with it (albeit more slowly than the pH if your TA is up high enough). So then sodium bi-carbonate is needed to raise the TA (raising the pH with it slowly). Then more acid is often needed again…. you get the picture.

The other byproduct of ongoing electrolosys (chlorine generation) is that the cyanuric acid (also called conditioner or stabilizer) is lowered over time. This will require additional cyanuric acid at least once to several times a season to boost the level and ensure the chlorine is “stabilized” and doesn’t dissappate prematurely due to ultraviolet rays from the sun.

2.) Corrosion. Salt is harsh on metals, rubber seals and just about everything else that is easily affected by a corrosive element. From pump seals to heater parts to diving board screws bolting them to the deck to stamped concrete decks we have seen corrosion play a role in saltwater pools over time. There are types of tile, coping, and decking that are more compatible with saltwater… however the affects of salt will still be there to some degree no matter how well a pool is designed and constructed.

I hope this information helps. I will do another post soon on ozonators. I believe a pool owner can get nearly all the pros of a saltwater system with virtually none of the cons for less money. Please shoot me an email if you would like information on an ozonator right away.