Glossary

Total alkalinity is the measure of the amount of alkaline buffers (primarily carbonates and bicarbonates) in your water. These alkaline substances buffer the water against sudden changes in pH, which result from people using your pool and spa. Total alkalinity is considered the key to water balance — and is therefore the first thing you should balance during routine water adjustments. 

Issues associated with alkalinity imbalance
If you neglect to check the total alkalinity in your pool or spa, you may have trouble balancing the pH. You may also notice that pH fluctuates suddenly despite your best efforts to keep it in the ideal range. If the alkalinity is too low, anything introduced to the water will have an immediate impact on pH. Abrupt shifts in pH can cause scaling or corrosion of metal equipment and fixtures as well as other problems. When the total alkalinity is high, the pH has a tendency to drift upward, causing scale to form.

Maintenance of alkalinity
Maintaining an ideal level of alkalinity will protect your pool or spa and its equipment from the harmful effects of sudden pH fluctuations. Think of the alkalinity as training wheels: it keeps the pH in balance without allowing it to tip too far to either side. Of course the pH can still drift upward or downward, but that change will happen gradually as long as the alkalinity falls within the ideal range. The ideal range of total alkalinity for pools and spas is between 80 and 120 ppm (mg/L).

When the total alkalinity is too low, add sodium bicarbonate. If the total alkalinity is too high, you can lower it by using muriatic acid or sodium bisulfate.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

Biguanide is a chlorine-free pool and spa sanitizer. (You many know Biguanide under brand names such as BAQUACIL® Chlorine-Free Swimming Pool Sanitizer and Algistat, BaquaSpa™ Sanitizer, SoftSwim™ Bactericide, PolyClear® MaxiPolish Swimming Pool Sanitizer and Algistat, or Revacil® Swimming Pool Sanitizer.)* Biguanide is a popular substitute for bromine and chlorine.

The Biguanide system is a 3-part system. Biguanide alone is only an effective sanitizer against bacteria. You must also apply weekly algaecide and shock treatments. Biguanide systems use hydrogen peroxide as a shock chemical; follow the directions of your dealer or manufacturer.

You should keep the Biguanide level in your pool or spa in the recommended range of 30 to 50 ppm (mg/L). Be sure to make the shock and algaecide treatments on a routine basis.

For more detailed advice on specific chemical treatment of your pool or spa, contact a pool care professional.

*BAQUACIL and BaquaSpa are trademarks of Avecia, Inc. SoftSwim is a trademark of Bio-Lab, Inc. PolyClear MaxiPolish is a trademark of Alden Leeds, Inc. Revacil is a trademark of Mareva, Inc. Use of these trademarks does not imply endorsement.

Bromine is a popular pool and spa sanitizer often used instead of chlorine — but it is distinctly different from chlorine in the following ways:

• Bromine works better than chlorine for spas and hot tubs (with hotter water and lower water volume).
  
• It is sensitive to sunlight, and deteriorates more rapidly than chlorine.
  
• Bromine is also typically more expensive than chlorine.

For these reasons, bromine is less popular than chlorine for use in outdoor pools.

Types of bromine
There are two forms of bromine: free and combined. Together, these two are called total bromine. Both types are sanitizers, meaning that they can kill bacteria, algae or other living organisms in the water. Be sure to use a test kit that measures total bromine, since that is the best indicator of the level of sanitizer in your water. The ideal concentration of total bromine in a swimming pool is 3 to 5 ppm. The ideal in a hot tub or spa is 4 to 6 ppm. (In spas the level should be slightly higher due to the smaller volume and the higher temperature of the water.)

Ongoing maintenance
Bromine should be monitored continually — almost daily — as it fluctuates often. Environmental conditions (like debris and rain) and usage (how many people are using the pool or spa) will add contaminants to the water, thereby reducing the bromine level. Always test bromine before entering the water. Even if the system is not in use, test the bromine level at least weekly to prevent build-up of bacteria or algae.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

Cyanuric acid acts as a "stabilizer" that helps chlorine hold up better when exposed to ultraviolet (UV) rays. You can think of it as slowing the process of sunlight breaking down the chlorine — like a sunscreen for your pool.

Maintain an ideal level of cyanuric acid, 30 to 50 ppm (mg/L), to prevent rapid chlorine loss.

Balancing cyanuric acid with other chemicals
If the cyanuric acid level is too low, you may need to add more. Be aware that cyanuric acid will also reduce your water's pH levels, so you may have to increase the pH as well.

Note also that too much cyanuric acid will reduce the beneficial effect of your chlorine, leading to stains or cloudy water — and some chlorine compounds already contain some cyanuric acid. If you are using dichlor or trichlor as your primary chlorine sanitizer, you are already introducing cyanuric acid along with the chlorine. If the cyanuric acid level is your pool or spa is too high, you will need to partially drain and refill with fresh water.

Maintenance
When you first fill your pool or spa, test the cyanuric acid level until you have added enough to reach the ideal range. After that, test cyanuric acid a minimum of once a month throughout the pool season. If you are using dichlor or trichlor, you will have to test cyanuric acid more frequently to ensure that the level has not exceeded the upper limit.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

Every sanitizer has two key functions: to sanitize (kill bacteria and all living organisms) and to oxidize (destroy contaminants and waste). The most popular pool and spa sanitizer is chlorine. Chlorine is also classified as a disinfectant, meaning that it is capable of killing bacteria, algae and other organic material instantly. All chlorine does the same thing when it is added to the water, regardless of the type of chlorine added: It forms free available chlorine. Free chlorine is the form of chlorine that kills bacteria, algae and disease-causing organisms.

The right balance of chlorine is important — too little, and your pool may not stay properly sanitized; too much and swimmers may experience skin irritation. Ideally, chlorine levels in a swimming pool should be about 1 to 3 ppm. In spas, the level should be higher — about 3 ppm to 5 ppm — due to the smaller volume and higher temperature.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

Water hardness occurs as an indirect side effect of various chemical compounds. Calcium and magnesium are the two primary minerals that make up hardness in water. Like alkalinity and pH, hardness affects the tendency of the water to be corrosive or scale-forming due to high mineral concentration.

Testing
The ideal level of hardness for your pool or spa water is from 200 – 400 ppm (mg/L).

You should test hardness when adding fresh water, and re-test until you have balanced the water hardness properly. After that, test hardness at least once a month throughout the season. If you use calcium hypochlorite as a sanitizer, you need to test more frequently to ensure that the level has not exceeded the upper limit.

Note: Low hardness levels require immediate attention

Water with low hardness will be very corrosive, causing significant damage to metal pipes and fixtures, as well as plaster. You must be sure to balance hardness before adding any sanitizer to the water. Otherwise, the water will become even more corrosive; it can cause severe damage in a short period of time. You can increase the hardness level by adding a chemical like calcium chloride.

Correcting high levels of hardness
When the hardness level is too high, excessive scale formation occurs, and the water may become cloudy or discolored. Elevated pH and warmer temperatures will increase scale build-up, too. If the hardness level is too high, you can partially drain and refill with fresh water.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

Monopersulfate is a strong oxidizer capable of eliminating contaminants from your pool or spa (hot tub). It can help you to maintain crystal clear water. Our AquaChek™ test strip measures Monopersulfate in the approximate range of 400 – 7,000 ppm (mg/L). The presence of chlorine or bromine may increase the reading of this strip.

You can use monopersulfate in two different ways:

• If the primary sanitizer in your pool or spa is chlorine or bromine, you can use monopersulfate as a shock chemical. This is something you do periodically when the contaminants have accumulated to a high level in the water. To shock the water, you raise the monopersulfate to a high level for a short period of time. It will oxidize (destroy) the contaminants that have accumulated in the water, helping your sanitizer get "caught up" with its job. Once the monopersulfate dissipates, the chlorine or bromine will resume destroying low levels of contaminants.
  
  
• You can also use monopersulfate in some alternate sanitizing systems in place of chlorine or bromine, although it still recommended that you maintain a minimal amount of one of those two in the water. Monopersulfate is used in several different mineral purification systems such as Nature2 and Frog®. In this case, you should test the water frequently to ensure that your water has a proper level of monopersulfate. Consult the chemical manufacturer's recommendation concerning the amount you should add to your water.

For more detailed advice on the chemical treatment of your pool or spa, contact a pool care professional.

We use pH as an index to express how acidic or basic a solution is. A pH greater than 7.0 is basic, and a pH lower than 7.0 is acidic. In pools and spas, it is important to maintain the water in the slightly basic range of 7.2 to 7.8. The National Spa and Pool Institute (NSPI), the industry association in the United States, has set a standard of 7.2 to 7.6 as the ideal pH. 

If pH is Low:

• The water can corrode surfaces, metal equipment or fixtures.
  
• Swimmers and bathers can experience discomfort from burning eyes and itchy skin.
  
• The chlorine may dissipate more quickly.
  
• The water may cause pitting and etching of plaster surfaces.

If pH is High:

• Calcium and metals tend to come out of solution (the opposite of dissolving) at high pH levels, creating the potential for staining and scale formation. The calcium and metals will actually create deposits and discoloration on pool walls and equipment.
  
• Swimmers and bathers can experience discomfort from burning eyes and itchy skin.
  
• High pH can contribute to cloudy water.

For more detailed advice on the specific chemical treatment for your pool or spa, contact your dealer.

The buffering capacity (total alkalinity) is important to maintaining pH in pond water. Adequate buffering capacity prevents sudden pH changes, which can cause stress to fish and aquatic plant life. The pH of your pond is constantly affected by factors such as rain, evaporation, photosynthesis of plants and ground water drainage into the pond. Buffers (carbonates and bicarbonates) absorb excess acids or bases introduced into the water.

Low buffering capacity will allow pH to swing from extreme highs to extreme lows, causing severe problems for fish and plants. High buffering capacity will cause the pH to drift upwards.

You should adjust buffering capacity before adding chemicals to adjust the pH. If the buffering capacity is too low, add sodium bicarbonate. If the buffering capacity is too high, adjust it down by adding a mild acid. Be sure to follow chemical manufacturer's recommendations when applying these chemicals, as they can be dangerous to you and your pond.

For more detailed information and advice on the specific treatment for your pond, contact your dealer.

Ammonia levels in a pond can build up from many causes:

• Uneaten fish food
  
• Fish waste
  
• Too many fish in a body of water that is too small
  
• Fertilizer run-of;
  
• Decaying plants and insects
  
• Any other source contributing high nitrogen levels to the water

Nitrogen undergoes a cycle that will convert to ammonia if allowed to build up. (Note that you can also test for two forms of nitrogen, nitrate and nitrite, with the AquaChek Four-Way Pond Kit.)

High levels of ammonia are extremely hazardous to fish and plant life, as are very low levels. Too much ammonia causes fish to have rapid gill movements, gasp at the surface and rub against underwater objects because of skin irritation. Ammonia can also prevent plants from getting the nutrients they need from the water.

You can lower ammonia levels by eliminating the source of nitrogen build-up and by neutralizing with a chemical solution that binds ammonia.

NOTE: If you choose to treat a high ammonia level with a chemical ammonia neutralizer, false positive readings may occur if you re-test with AquaChek Ammonia soon after treatment. Wait 48 hours before re-testing to allow your pond filtration system to thoroughly remove the neutralized ammonia.

For more detailed information on the specific chemical treatment for your pond, contact your dealer.

A proper pH will prevent the harmful effects of water that is too acidic or alkaline. The pH is a measure of how acidic or basic the water is. It is measured on a scale of 0 – 14. A pH of 7.0 is neutral. A pH greater than 7.0 is basic (alkaline), and the larger the number the more basic the water. A pH less than 7.0 is acidic, and the smaller the number the more acidic the water.

You should maintain the pH at neutral or slightly basic, around 7.0 or just a little higher.

Issues with unbalanced pH levels
The water should not be less than 7.0 for most ponds. Low pH is toxic to fish. Water that is too acidic can cause fish to gasp at the surface and reduce their resistance to disease. Plants show stunted growth, and useful bacteria are not effective. At the opposite extreme, an elevated pH increases the toxicity of ammonia. High pH causes fish to have fungus, diseases, respiratory trouble and discoloration; plants and bacteria don't grow well.

You can adjust the pH up or down using various chemicals when necessary. When adjusting pH, do not change the pH in your pond by more than 0.2 pH units per day. Sudden pH changes that are greater than 0.2 pH units can cause stress and illness for fish and plants.

For more detailed advice on the specific chemical treatment for your pond, contact your dealer.

After bacteria break down ammonia into nitrites, a second group of bacteria break down toxic nitrites into nitrate, which can be beneficial to aquatic plants. Proper nitrate levels promote plant growth and are harmless to any fish in the system.

High nitrate levels lead to rapid algae growth, and may harm fish. They can also lead to the formation of other harmful nitrogen compounds, nitrite and ammonia. Amber-tinted water may indicate high nitrate levels.

Nitrate levels in a pond can build up from the same sources that cause elevated nitrites:

• Uneaten fish food
  
• Fish waste
  
• Too many fish in a body of water that is too small
  
• Fertilizer run-off
  
• Decaying plants and insects
  
• Any other source contributing high nitrogen levels to the water

Prevent nitrate build-up by controlling feeding and fish population. Also monitor the nitrate levels so that you can neutralize them before they are converted to more harmful forms. You can control nitrate levels by using various chemicals when necessary.

For more detailed advice on the specific chemical treatment for your pond, contact your dealer.

Nitrite levels in a pond can build up from various sources:

• Uneaten fish food
  
• Fish waste
  
• Too many fish in a body of water that is too small
  
• Fertilizer run-off
  
• Decaying plants and insects
  
• Any other source contributing high nitrogen levels to the water

The high nitrogen levels undergo a cycle that will convert to nitrite if they are allowed to build up.

High levels of nitrites are toxic to fish, causing them to become listless, discolored and deprived of oxygen. High levels can also encourage rapid algae growth. Toxic nitrite results after a group of beneficial bacteria causes the breakdown of Ammonia.
Nitrite can be controlled using a chemical compound that neutralizes nitrites and prevents them from being problematic.

For more detailed advice on the specific chemical treatment for your pond, contact your dealer.

Many swimming pools and spas use an automated generator that converts sodium chloride into chlorine. These chlorine generator systems require that you measure the salt content of the water on a regular basis. If the salt level gets too high, you can damage your generator. If the level is too low, the system won't be able to sanitize your water adequately.

The ideal level of salt content varies according to the manufacturer. If you have a chorine generator, it is critical that you maintain the sodium chloride level in the ideal range recommended by the manufacturer of your generator system. This will help your generator to sanitize the water properly, keeping it sparkling clear and clean.

For more detailed advice on specific chemical treatment of your pool or spa, contact a pool care professional.

Chlorine in pool and spa water may be present in two forms: free chlorine and combined chlorine.

Free chlorine does the hard work of killing bacteria and oxidizing contaminants. (When you add a chlorine compound like Cal-Hypo or trichlor to your pool, you are actually adding free chlorine.)

When free chlorine combines with contaminants such as oils, swimmer waste and other organic compounds, it becomes combined chlorine, or chloramines. In pool and spa water, this form of chlorine has very little sanitizing ability, and no oxidizing ability.

Your water's total chlorine level is the sum of combined chlorine and free chlorine. If the total chlorine level is higher than free chlorine alone, then combined chlorine is present. In this case you'll need to shock or super-chlorinate your pool or spa. To shock the pool, add a free chlorine compound in an extra large dose. The high dosage of free chlorine will actually eliminate the combined chlorine.

For more detailed advice on the chemical treatment of your pool or spa, contact a pool care professional.