November 2011
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Changing Your Hot Tub Water in 4 Simple Steps
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How to Choose the Right In-ground Pool for You
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Whenever you look at the test results for your pool water, you encounter a host of acronyms that can prove difficult to keep straight. Knowing what your levels are should be your first concern, but it is also helpful to understand why. This pool water testing guide will explain some of those chemistry terms and why they’re important.
Understanding pH
Understanding pH is one of the most important aspects of pool care. pH has the greatest effect on water balance and sanitizer effectiveness. pH, or potential hydrogen, is a measure of how acidic (vinegar) or basic (dishwashing detergent) your pool water is. pH is measured on a scale ranging from zero, which is the most acidic, to 14, the most basic. A pH of seven is considered neutral. Always keep the pH range within the recommended guidelines. If your pool water has a pH below the recommended range, the acidity of the water increases the likelihood that swimmers will experience skin and eye irritation. Low pH can also corrode your pool equipment and metal piping, which can cause metals to leak into your water resulting in discoloration, says Touraj Rowhani, research chemist at Arch Chemicals, Inc. A pH greater than the recommended range can cause cloudy water and contribute to scale formation, as well as irritating swimmers’ eyes and skin.
Sanitizer [Chlorine and Chlorine-Free]
The main purpose of your pool sanitizer is to kill bacteria, control algae and destroy organic contaminants. Maintaining the proper sanitizer level is important to the health of your swimmers, and it plays a big part in preventing algae growth, Rowhani says. Always keep your sanitizer levels within the recommended parameters. Test and adjust regularly.
Total Alkalinity
Total alkalinity, or TA, refers to the quantity of alkaline materials dissolved in the pool water, which act as a buffer in controlling pH change. TA that is too high could cause your pH to shoot up resulting in cloudy water or scale. TA that is too low won’t be able to successfully protect your water from sharp pH fluctuations, and the pool water may promote corrosion and cause damage to pool fixtures and equipment. Although a general rule of thumb is to maintain a TA level between 80-120 ppm, the ideal TA level for your pool depends on what sanitizer you use.
Calcium Hardness
All water contains some natural hardness (calcium and magnesium), which will vary by geographic region and by source within a region. Calcium hardness refers to the amount of dissolved calcium in your water. The optimal range is between 200-500 ppm, as anything higher than 1000 ppm increases the potential for cloudy water and scale buildup, Rowhani says. Levels below 200 ppm can corrode pool equipment. In plaster pools it may result in pitting or etching problems.
Stabilizer or Conditioner
Stabilizer, also referred to as Conditioner, is cyanuric acid. It works to keep chlorine in the water longer and protects the chlorine against ultraviolet light. Conditioner is most effective when its concentration is between 25-50 ppm.
Testing
You can use home testing kits to test for all of the items discussed so far. For a quick reference on what to test and how often, please see our chart below.
POOLLife® magazine recommends that you take a pool water sample to your professional dealer monthly — they will test the water using more sophisticated equipment to provide you with a more accurate reading. Your dealer will also test your Total Dissolved Solids (TDS) levels and check to see if you have any metals present in the water. Metals can leak into the water from corroding metal piping or pool equipment. “When this happens, the consequences can be staining, high sanitizer consumption and discolored water,” Rowhani says. The TDS level should be kept below 2000 ppm. If your pool has too much TDS, it can interfere with the ability of sanitizer to do its job.
Maintaining the proper levels for each of the water balance factors above is really easy and is the key to having a carefree and enjoyable pool season.
Testing Chart
Use the chart below as a guide to help you determine what factors you should test your water for and how often. The chart also explains when you should bring a sample to your dealer.
| Legend | |
|---|---|
| Tested by Pool Owner | X |
| Tested by Professional Dealer | X* |
| Water Balance Factor | Daily | Weekly | Monthly | Open | Close |
|---|---|---|---|---|---|
| pH | X | X* | X* | ||
| Sanitizer [POOLIFE/Pool Breeze®] | X | X* | X* | X* | |
| Sanitizer [BAQUACIL®] | X | X* | X* | ||
| Oxidizer [BAQUACIL® CDX™ SYSTEM] | X | X* | X* | X* | |
| Total Alkalinity (TA) | X | X* | X* | X* | |
| Calcium Hardness | X* | X* | X* | ||
| Total Dissolved Solids | X* | X* | |||
| Metals | X* | X* | X* | ||
| Stabilizer (cyanuric acid) | X* | X* | X* |
