Chlorine generators make chlorine slowly and are not capable of shocking the water. If you want or need to shock the water then you will need to manually add the shock treatment.

When you get a saltwater chlorine generator you are making a statement that you are going to be buying and using fewer chemicals, and part of the reduced maintenance is that you don’t have to check your pool chemical balance very often. This isn’t entirely true, you may still need to periodically shock the water and you should measure the chemical balance prior to use if it is a spa and at least once a week if a pool. Over time the chlorine demand of the water will go up as more and more organic material enter the water. A point may be reached where the chlorine demand for the water is the same or exceeds the chlorine output from your electronic chlorinator. You will notice that when the chlorine is low it takes longer over time for it to bring the chlorine levels back up. You may also have to increase the power level to make more chlorine as the water is consuming more chlorine than your chlorine generator can make at the lower power level. This is more likely to happen in a Spa that is used often and if you have a spa chlorine generator. A Spa chlorinator is designed to make much less chlorine than a pool chlorinator as you do not want to over-chlorinate your spa which could lead to corrosion.

Pool or spa shocking is the addition of a sufficient dose of chlorine: calcium hypochlorite (cal-hypo), liquid chlorine, sodium dichlor or non-chlorine shock (potassium monopersulfate or MPS). The purpose of a shock treatment is to break-down organic waste contaminants which cause odor, cloudy water, and a decrease in the efficiency of saltwater chlorinators. After treatment, water quality and clarity are often completely restored and you may be able to lower the power level of the saltwater chlorine generator.

When a spa is used every day there can be a quick buildup of organic material, and the water may look just fine and not smell, but the spa chlorine generator is having a harder time keeping up as the days go buy. If you increase the power level of the spa chlorinator that will also decrease the life span of the chlorinator as it will be on longer each day. Shocking the spa is a better alternative and you have to decide on a chlorine or chlorine-free shock.

• If you don’t want to add chlorine, then the chlorine-free shock is the way to go. Just follow the directions on the container.
• If you don’t mind adding chlorine the spa chlorine generator will not mind. This will shock the spa water, and give it some chlorine which is less chlorine that the electronic chlorinator has to make.

The life span of a pool and spa Chlorine Generator is determined by many factors, but perhaps the most important are:

• Current density, the current per square inch between the plates
• If self cleaning, the period of time between reversing polarity
• Length of chlorine production time

Current density

The current density is one thing that you, the owner of the chlorine generator can have little effect on. The only things that you can do are to set the water temperature and the salt level. The other things that effect the current density are in the design of the cell and the power supply.

The titanium plates typically have a life span of 10,000 hours of chlorine production with the current density at 0.2 amps per square inch. At 0.4 amps per square inch, the life span would be cut in half or even less, but the amount of chlorine produced would also go up.

The factors that effect the current density include

• Spacing between the plates
• Voltage applied to the plates
• Conductivity of the water

 Spacing between the plates: As the plates get closer together the current will go up for the same voltage. The spacing between plates and the voltage are part of the design of the chlorine generator and the manufacturer will typically give a recommended salt concentration which would provide the proper current density for the spacing and voltage of the chlorinator. The proper current density should be one that will exceed the warranty period of the chlorinator. If there is more salt then the current would be higher, if there was less salt the current would be lower.

 Voltage applied to the plates: Some chlorine generators have the ability to change the voltage to keep the current density constant. These will be able to work with greater salt concentration ranges and water temperatures.

 Conductivity of the water: The primary factors are salt concentration and water temperature. As the temperature goes up the current density also goes up. A pool chlorine generator would probably be designed for the proper current density at 80 degrees Fahrenheit. To use a pool chlorine generator in a spa, where the water is 104 degrees Fahrenheit could be a very big problem. At the higher temperature the current density would go up quite a bit and it would also make a lot more chlorine. You would probably not be able to adjust it low enough to make the right amount of chlorine. Over-chlorination can lead to corrosion of the spa heater and other parts. You can of course in this example keep the salt low or make sure that your chlorinator is the type that adjusts the voltage.

 Reversing Polarity

If you have a reversing polarity chlorine generator, then the coating on the titanium plates probably has a blend with Ruthenium Oxide. Every time the plate voltage reverses that can decrease the life of the plates but when done properly the cell will still meet the life expectancy of the chlorine generator. This is a function of the chlorine generator design.

 With the non-reversing chlorine generator the plates will need to be cleaned more often. The manual cleaning probably also effects the life of the plates.

 Length of Chlorine Production

This is the one factor that the owner of the chlorine generator can have a big impact on. The longer the chlorinator is on, that is getting closer to the life of the cell. You will get a longer life from the cell if you are able to have it on less. This of course leads to the chlorine demand of the water and the chlorine level you are trying to achieve. Some of the factors that can help to reduce the time per day the chlorine generator needs to be on include:

Table of things you can do to lower chlorine demand

Conclusion

Always follow the manufacturers recommended salt concentration for your chlorine generator. There are quite a few things you can do to help reduce the chlorine demand on your pool or spa, pick the ones that you can easily do and hopefully you will be able to lower the output level on your chlorine generator, make sure to measure the free chlorine every couple days.

written by Scott Lenney at  www.controlomatic.com

 Chlorine generators, also called chlorinators make chlorine from salt that you have added to the water making it saltwater. Chlorinators have titanium plates with a special coating that when voltage is applied causes electrolysis and the breakdown of the water and the salt creating hydrogen, oxygen and chlorine. The plates have a life span that is typically 10,000 hours of chlorine production if the current to the titanium plates is kept below 0.2 amps per square inch. As the current increases above this value the life span of the plates drops to a value less than 10,000 hours. The current density is determined by the voltage applied to the plates and the spacing of the plates. And, the higher the current the higher the chlorine production (in most cases).

 Lower cost chlorinators typically exceed the 0.2 amps to require less titanium in the product as the titanium and the coating is the most expensive part and they can provide a lower cost product that will not last as long. For a swimming pool this may not be a problem for a one or two year warranty as the season for a pool is 5 months, and if it is on for 12 hours per day then in two years the chlorine generator would have only been on 3650 hours. Even if there is a longer warranty that may not matter as the manufacturer figures what are the chances after two years for a warranty claim.

When looking to purchase a chlorine generator and talking to your friends who have one it isn’t enough that they like the product. Almost everyone who has converted to a saltwater chlorine generator likes the change. When reading a blog about a particular chlorinator and the excitement of the writer on how wonderful the water is and how they endorse that particular product is sort of silly, especially if they bought a cheap one which makes lots of chlorine the first months due to the high current to the plates and they are in their first month. Instead look to those who recommend a chlorine generator where they are past the first year and any problems they may have had the manufacturer has backed up the warranty and service.