Many pool water and surface issues can be handled by the pool owner. The Pool Care Troubleshooting Guide provides solutions to some common pool issues. Proper water chemistry is key to a properly balanced pool.
Often, many water and surface problems can be handled by the individual pool owner. The information below provides solutions to some common pool issues. Always make sure the water is properly balanced prior to any addition of corrective chemicals.
Read more on Algae Maintenance.
Total alkalinity refers to the ability of the pool water to resist a change in pH. The key purpose total alkalinity serves is to help control the pH in the pool. It does this by acting as a buffer so that when materials are added to a pool that would otherwise cause the pH to go up or down, these changes are managed and do not result in severe changes to pool water balance.
When a substance is added to pool water that could affect the pH, total alkalinity will react to neutralize it and help keep the pH in the desired range. Total alkalinity does not determine what the pH will be, but rather acts to help keep the pH in the range desired.
Total alkalinity is measured in parts per million (ppm) using a total alkalinity test kit. It is best kept in the range of 80-120 ppm. When the total alkalinity value is less than 80 ppm, the water can become aggressive and the pH can swing easily upward and downward and back again. If the value is higher than 120 ppm the water can become cloudy and scale forming and the pH will tend to drift upward.
In adjusting total alkalinity downward, the same acids used to lower pH are employed. When reducing total alkalinity, it is best to add small amounts of acid, either liquid or dry, over a period of several days as opposed to making large adjustments rapidly. Adding too much acid at once may result in lowering the pH so severely that corrosion of pool surfaces and equipment may result. When raising total alkalinity, alkalinity increaser is the chemical of choice. Adding the required amount in recommended increments over a few hours with the pool circulating is suggested. Please be aware that some clouding could occur.
What is alkalinity?
Algae growth is perhaps the most obvious sign of something gone wrong with pool maintenance. Proper maintenance will not only keep your water looking great, but also allow for easy prevention of algae growth.
There are two basic groups of algae:
Black algae is the common name or term given to the dark blue-green algae found growing on pool surfaces. Black algae grows in localized areas such as along one wall, in the deep end, in a corner or around obstacles such as steps indicates an area of poor circulation and poor sanitization.
- Free-floating types including green and mustard varieties. These tend to be found throughout the water. Mustard algae tends to cling loosely to the walls of the pool and brushes off easily. It tends to have a yellowish color. Green algae will be visible throughout the water itself and will turn the water different shades of green depending on the infestation.
- Black algae is the common name or term given to the dark blue-green algae found growing on pool surfaces. Black algae grows in localized areas such as along one wall, in the deep end, in a corner or around obstacles such as steps indicates an area of poor circulation and poor sanitization.
The growth of both types of algae can be easily prevented by using a quality algaecide as part of a regular maintenance program, and by proper circulation. It takes far less algaecide to prevent algae growth from getting started than it will to cure it once it has occurred.
The regular use of algaecide is also recommended to prevent problems should a failure of the sanitization program occur. Due to the unique nature of chlorine or bromine, these residuals can often be lost very quickly in pools due to equipment or operator error or by heavy rainfall or bather waste demand. Improper water balance will contribute to the ability of your sanitizer to work properly and prevent algae growth. If this occurs without an algaecide present, the rapid growth of algae can occur in a few hours. However, if an algaecide is present, it will act as algae growth prevention (look at it as an insurance program) until the sanitizer system is functioning normally.
In spite of your best efforts, algae problems can occur and require some consideration for proper treatment. When an algaecide becomes necessary, the following factors need to be considered before treatment:
Amount of algae present
It is critical that sufficient algaecide is added to treat all of the algae at one time. The use of only some of the needed algaecide will not kill some of the algae. It is important to follow the directions for use on the package.
Age of the algae
The older algae becomes, the more difficult it is to control. Treat the problem as soon as it is noticed.
Sunlight and water temperature
It is best to treat when algae are actively growing. Sunny days and a water temperature of 60°F or higher will be helpful.
Yellow or Mustard Algae
Yellow or mustard algae is very similar in form to green algae, but is much slower growing and is deficient in chlorophyll (green pigment) which accounts for its yellow color. It is easily identified by the ability to brush it easily off the pool walls and floor. Because yellow algae grow very slowly, it is also very difficult to destroy. By the time you see it growing in your pool, it has likely been there as long as several weeks. Additionally, since yellow algae is low in chlorophyll which is light-loving, the algae live and even grow in dark areas of the pool such as plumbing and filters. This only compounds the difficulty of control. To treat mustard algae, care in selection of a proper algaecide is most important. Be certain to select a product made for the control of this unique form of algae. Copper-based algaecides seem particularly well suited for controlling yellow algae. One word of caution: it is not unusual to need to treat yellow algae more than once to bring it fully under control. This again points out the value of preventing the growth in the first place.
Because chlorine likes to combine with other elements in the water, it is effective at killing bacteria when they combine. However, when ammonia is present in the water, the two combine to form chloramines. When combined, the chlorine is in a weakened state and is not as effective against algae and bacteria.
Ammonia (Nitrogen) in the water can come from human sweat, urine, leaves and fertilizer. Because one active swimmer in the water can produce one quart of sweat in an hour, it is highly likely that ammonia will be present. When you smell chlorine in a pool or have irritated eyes, chloramines are the cause – not the presence of too much chlorine. Chlorine gets a bad rap in this case. Chlorine is by far the most efficient and effective way to control algae and bacteria in your pool. The only way to reduce the chloramines is to add more chlorine, shock, to neutralize the chloramines so that the chlorine will go back to oxidizing the bacteria and algae instead of combining with the ammonia in the water.
You can calculate combined chlorine in your water by subtracting the amount of free chlorine from total chlorine. This value should be as close to zero as possible. Whether your pool is used heavily or not, chloramines can form in your pool. Shocking on a weekly or biweekly basis is required.
You need to be sure that your pool water has adequate circulation, filtration and chemical treatment so that it remains clean and clear. There are a number of causes for cloudy water. This would include:
- Low chlorine
- pH and/or alkalinity too high
- High calcium hardness
- Pool circulation and filtration.
- Water Temperature. As the water heats up during the spring and summer, it is more susceptible to clouding.
In order to maintain adequate circulation, you should run your pool pump at least 12 hours during the summer and 6-8 hours during the winter (pool pumps are designed to run 24 hours. This will most assuredly help prevent cloudy water). Be sure to test your water regularly and add necessary chemicals to ensure proper balance. If you pool needs to be shocked, shock it and run the filter for at least 24 hours to see if that clears it up.
If your pool water still remains cloudy, contact a pool professional to test and clarify your water. Be sure the pool professional checks your equipment to be sure it is working properly. You should also be sure your filter is cleaned at least twice a year.
pH is the term used to refer to the degree of activity of an acid or base (alkali) in the water. It is the most important chemical factor to be maintained in swimming pools. pH is measured on a scale from O to 14 with 7 being neutral. Pool water pH is best when kept in the range of 7.2 to 7.8.
A value of 7 to 14 is considered basic with 14 being the greatest base activity. Another word for basic is alkaline; however, this is not to be confused with total alkalinity. pH and total alkalinity are not the same but can be influenced by each other.
A pH value between 0 and 7 is considered acidic with 0 being the greatest acid activity and getting weaker as it approaches a value of 7. When pH remains below 7.2, the water is considered to be corrosive. This means etching of plaster and metals in equipment such as heat exchangers will result. In addition, it is more difficult to keep chlorine in the pool because while more effective as a sanitizer at the low pH, chlorine is also much less stable resulting in the consumption of larger quantities of chlorine than would be used at normal pH levels.
Maintaining the pH higher than 7.8 will increase the tendency to form scale or cloudy water. Calcium, the major component in scale, is a relatively unstable mineral and when the pH is high, the calcium is not as soluble and it will have a greater tendency to precipitate or "fall out" of solution resulting in cloudiness or scale. High pH will also reduce chlorine effectiveness resulting in the need to maintain higher chlorine levels to achieve maximum sanitization. If the pH is low, a pH increaser is added to raise the pH. If the pH is high, pH Down is used. pH Down comes in two forms: liquid acid or dry acid.
Changes in the pH of pool water can be caused by many factors but one of the most significant cause is the sanitizer used. Since the sanitizer is the most frequently added chemical in pools, it can have a powerful impact on pH and overall water quality.
Of the sanitizers typically used in pools, chlorine is the most common. Chlorine comes in a variety of forms and varies widely in pH. For example, most tableted forms of chlorine have a very low pH and will tend to lower pH over time, while liquid chlorine is very high in pH and will tend to raise pH values. Salt is also very alkaline and will require frequent additions of acid to maintain the proper pH and overall water balance.
Changes in pH due to sanitizers or other factors can be minimized and controlled by the proper maintenance of the next chemical factor, total alkalinity.
What is pH?
The sum of all the calcium dissolved in water is referred to as the calcium hardness. Calcium is important since high levels are unstable and become even more unstable if the pH or the total alkalinity rise above the normal levels. These imbalances can result in cloudy water and/or scale. In addition, calcium does not like warm water. As water temperature rises, calcium becomes more likely to precipitate out of solution. Calcium is actually more soluble in cold water, which is why scaling of heater equipment is so common.
With all of the difficulties calcium can cause, it would seem logical to use soft water in filling a pool. However, this is not the case! While high calcium levels can cause problems with cloudy water and scale, soft or low-calcium water is also of concern. Such water is aggressive and will actually remove calcium from plaster in order to satisfy its need for the mineral. If the pool is vinyl or fiberglass, the low calcium water will actually attack metal fittings and heat exchangers resulting in destruction of the fittings or pinhole leaks in the heater. When such corrosion occurs, it is also common for stains to appear on pool surfaces. It will also damage the vinyl or fiberglass surface you may have.
Calcium content is best in the range of 100-400 ppm and is water temperature dependent. Unlike pH or total alkalinity, however, both of which can be raised or lowered with reasonable ease, calcium levels cannot.
Adding a hardness increaser to the water easily raises calcium levels. Conversely, there is no simple chemical addition that can be made that will reduce calcium hardness. The only way to reduce calcium hardness levels in pool water is through dilution with water of a lesser hardness. Over time, calcium hardness will naturally increase in pool water due to evaporation and possibly other factors unless the pool water is regularly diluted.
While it may be difficult to reduce calcium hardness, it is possible to control it so that a potential problem such as cloudy water or scale formation is prevented. The best way to minimize the effect of high calcium levels is through the use of a sequestering agent. A sequestering agent is a compound that, when added to water, will chemically bond with calcium and other minerals to make them, in a sense, more soluble. This means that calcium will still be present, but in a form that is less likely to cloud water or form scale if the pH or other factors get out of balance. In addition, since calcium will still be in the water, you will not have the corrosion problems you would otherwise experience with soft water. A further advantage is that elevated levels of calcium (over 400 ppm) can be tolerated without constant need for dilution. This becomes especially important when the pool is located in hard water areas or calcium-based chlorine sources are used. A sequestering agent should be a part of your regular chemical maintenance program.
When dealing with calcium harness issues in your pool, it is suggested that your first line of defense is your local pool professional. They can prescribe what is best for your pool to take care of and prevent any problem that can arise.