Salt Water Chlorine Generator Basics
The following is a good recommendation for SWCG’s:
The following water balance tips for SWCG’s will help you maintain your pool with the fewest problems. Following them closely will mean that you will probably never need to shock your pool, and you will maintain a more stable pH than if you go outside of these suggested limits. They may or may not agree exactly with what the manufacturer’s recommend, but they do work and will help you maintain your salt pool easier.
The first step is to adjust the salt level to the manufacturer’s recommended range, which is usually between 2,800 and 3,200 ppm. Add the salt slowly (maybe 2 bags in the morning, another 2 at lunch and 2 more in the evening). Once you think you are getting close, check the levels with strips or a meter (do not trust the salt cell, as they are not always real accurate!). Remember that you can always add more salt, but it is difficult to remove too much!
Next, adjust the CYA (Cyanuric Acid, conditioner, stabilizer) to between 60 and 80. One of the biggest mistakes that many SWCG owners make is not having enough CYA in the water. As with salt, add the CYA slowly (It can take up to a week for the CYA to assimilate into the water, and, like salt, too much is a task to remove. In the case of CYA, too much will also impede the ability of chlorine to do its job.) This can create a lot of problems with the water, like higher acid demand, algae, cloudy water, or even early cell failure.
Set your pump to run a minimum of 8 hours a day initially, and adjust the output of the SWCG so that your free chlorine level stays between 3-5 ppm. Running the pump shorter than 8 hours can keep your pool sanitized, although it will require a higher chlorine generation level, which will shorten the cell life. Make sure that if you are using a 2 speed or multi-speed pump that you have it set high enough to activate the SWCG’s flow switch.
You will want to adjust your TA (Total Alkalinity) to between 60-90 ppm. This is very important, as this is beneficial in buffering the pH.
You will next need to adjust your pH to 7.5-7.6, but not any lower. Monitor your pH and when it climbs to 7.8 add acid to lower it back to 7.5-7.6. It is very important that you maintain these parameters to avoid scaling.
Calcium Hardness (CH) needs to be between 200-400 ppm for plaster pools, and 250 ppm for fiberglass pools. Vinyl pools are alright if the CH is at 50 ppm, or higher (check your equipment manufacturers specifications for calcium levels as well. Too low of calcium in the water will void some manufacturers warranties.). You should not be much above 400 ppm, or you will have to keep a close watch on your pH to prevent scale build up in the cell. You may find that sometimes your fill water will have high calcium levels, and your numbers are higher than recommended. This is prevalent in states in the south mostly. It is not really that big of an issue as long as you maintain your pH as recommended above, although CH of greater than 400 ppm is not ideal. pH rise is probably the most common part of your waters chemistry that will predict scaling condition. High pH leads to scaling; always! it is imperative to keep your pH below 8.0 to prevent scaling.
You might also consider adding borates to the pool, in a 30-50 ppm concentration. This will help pH stability with a SWCG; particularly when the TA is kept in the 60-90 ppm range, and pH is kept between 7.5-7.8. However, it can be useful even if you go out of this range, to some degree. 20 Mule Team Borax is the most common borate product, although there are others, and this can be purchased at most grocery stores. It is typically found in the laundry aisle. It is important to understand how to add borates, so please post if you do not know and we will get you started.
FC wants to be between 3-5 ppm, based on an eight (8) hour run time, or longer.
pH needs to be maintained between 7.5-7.8
TA must be in the 60-90 ppm range.
Calcium Hardness (CH) should be:
50 ppm (minimum) for vinyl
250 ppm for fiberglass
200-400 ppm for plaster
CYA between 60-80, although some manufacturers suggest up to 100 ppm (usually requires higher FC at this level).
Salt between 2,800-3,200 (remember, you can always add more, but it is difficult to remove excess).
Borates are optional, and should be between 30-50 ppm, if used.