If you have a salt water pool, you might be surprised to see it turn green one day. You might think that salt water pools are immune to algae, the common cause of green water in pools. However, this is not true. Salt water pools can also get algae, and it can be a serious problem if not treated properly.
In this article, we will explain why salt water pools can turn green, how to identify the type of algae in your pool, and how to get rid of it and prevent it from coming back.
What Causes Algae in Salt Water Pools?
Salt water pools use a salt cell or generator to convert salt into chlorine, which sanitizes the pool water. However, this does not mean that salt water pools have enough chlorine to kill all algae spores. Algae spores can enter your pool from various sources, such as wind, rain, swimsuits, floats, or pool equipment. If the chlorine level in your pool is too low, or if the water is out of balance, algae can grow and multiply rapidly in your pool.
Some factors that can contribute to algae growth in salt water pools are:
- Low or inconsistent salt level: If the salt level in your pool is too low, the salt cell will not be able to produce enough chlorine to sanitize the pool. You should check the salt level regularly and add more salt if needed. The ideal salt level for most salt water pools is between 2700 and 3400 parts per million (ppm).
- Low or inconsistent chlorine level: Even if the salt level is adequate, the chlorine level in your pool can fluctuate due to various factors, such as sunlight, temperature, bather load, or organic contaminants. You should test the chlorine level regularly and adjust it if needed. The ideal chlorine level for most salt water pools is between 1 and 3 ppm.
- High or low pH: The pH level of your pool affects the effectiveness of chlorine. If the pH is too high, chlorine will become less active and less able to kill algae. If the pH is too low, chlorine will become more active and more likely to cause irritation to swimmers and damage to pool surfaces and equipment. You should test the pH level regularly and adjust it if needed. The ideal pH level for most saltwater pools is between 7.2 and 7.6.
- High or low alkalinity: The alkalinity level of your pool affects the stability of the pH. If the alkalinity is too high, the pH will become more resistant to change and more likely to cause scaling and cloudy water. If the alkalinity is too low, pH will become more prone to change and more likely to cause corrosion and staining. You should test the alkalinity level regularly and adjust it if needed. The ideal alkalinity level for most saltwater pools is between 80 and 120 ppm.
- High or low cyanuric acid (CYA): CYA is a stabilizer that protects chlorine from being degraded by sunlight. However, if CYA is too high, it will also reduce the effectiveness of chlorine and make it harder to kill algae. If CYA is too low, the chlorine will be consumed quickly by sunlight and making it harder to maintain a consistent chlorine level. You should test the CYA level regularly and adjust it if needed. The ideal CYA level for most salt water pools is between 30 and 50 ppm.
and how to identify and get rid of them.
How to Identify and Get Rid of Different Types of Algae in a Salt Water Pool
Green algae are the most common type of algae found in saltwater pools. They are easy to spot as they appear as green, slimy patches on pool walls and floors. Green algae grow rapidly in warm temperatures and bright sunlight, making them more common during the summer months. They can cause cloudy pool water and give the pool a greenish tint.
To get rid of green algae, you need to shock your pool with a high dose of chlorine. You can use either liquid chlorine or granular chlorine, but make sure you follow the instructions on the label carefully. You should aim for a chlorine level of at least 10 parts per million (ppm) for several hours until the algae are killed. You may need to repeat the shock treatment if the algae are persistent.
You also need to brush the pool surfaces with a pool brush to loosen the algae and vacuum the dead algae out of the pool. You should also clean your filter and skimmer basket to remove any algae that may have clogged them. You can use a pool algaecide as a preventive measure, but it is not necessary if you maintain a proper chlorine level in your pool.
Yellow or Mustard Algae
Yellow or mustard algae look a bit like clumps of sand or pollen in the water. They are usually found in shady areas of the pool or on pool equipment that is not used often. They are more resistant to chlorine than green algae and can survive in low-chlorine conditions.
To get rid of yellow or mustard algae, you need to shock your pool with a higher dose of chlorine than for green algae. You should aim for a chlorine level of at least 15 ppm for several hours until the algae are killed. You may also need to use a special algaecide that is designed for yellow or mustard algae, such as sodium bromide or ammonium sulfate.
You also need to brush and vacuum the pool thoroughly and clean your filter and skimmer basket. You should also remove any pool equipment that may have been infected by the algae and soak them in a bleach solution for at least an hour. You should also check your salt chlorine generator and make sure it is working properly and producing enough chlorine for your pool.
Black algae are the most difficult type of algae to get rid of. They appear as black spots on pool surfaces, especially on plaster or concrete pools. They have a protective layer that makes them resistant to chlorine and brushing. They can also spread through their roots that penetrate into the pool surface.
To get rid of black algae, you need to shock your pool with a very high dose of chlorine, at least 30 ppm, for several days until the algae are killed. You may also need to use a special algaecide that is designed for black algae, such as copper sulfate or silver nitrate.
You also need to scrub the black spots with a stiff brush or a pumice stone to break their protective layer and expose their roots. You may need to use a metal file or a drill to remove their roots from the pool surface. You should also vacuum the dead algae out of the pool and clean your filter and skimmer basket. You should also check your pH level and make sure it is not too high, as this can encourage black algae growth.
Pink slime is not actually an algae, but a type of bacteria that can grow in saltwater pools. It appears as pink, slimy patches on pool surfaces, especially on plastic or vinyl materials. It can cause cloudy water, foul odor, and skin irritation.
To get rid of pink slime, you need to shock your pool with a high dose of chlorine, at least 10 ppm, for several hours until the bacteria are killed. You may also need to use a special algaecide that is designed for pink slime, such as polyquat 60 or benzalkonium chloride.
You also need to scrub and vacuum the pool thoroughly and clean your filter and skimmer basket. You should also remove any pool equipment that may have been infected by the bacteria and soak them in a bleach solution for at least an hour. You should also check your salt level and make sure it is not too low, as this can encourage pink slime growth.
How to Prevent Algae from Coming Back
Once you have cleared your saltwater pool of algae, you want to keep it that way. Here are some tips to prevent algae from coming back:
- Test your water regularly and maintain proper chemistry levels. You should aim for a pH level of 7.2 to 7.6, a total alkalinity level of 80 to 120 ppm, a calcium hardness level of 200 to 400 ppm, and a salt level of 2700 to 3400 ppm.
- Keep your chlorine level between 1 and 3 ppm at all times. You can use a salt chlorine generator to produce chlorine from salt, but make sure you check its performance and clean its cell regularly. You can also use a chlorine stabilizer, such as cyanuric acid, to prevent chlorine loss due to sunlight.
- Run your pump and filter for at least 8 hours a day to ensure proper circulation and filtration of your pool water. You should also backwash your filter and clean your skimmer basket regularly to remove any debris that may clog them.
- Brush your pool walls and floor at least once a week to prevent algae from sticking to them. You should also vacuum your pool regularly to remove any dirt or organic matter that may feed algae.
- Use a pool cover when your pool is not in use to reduce evaporation, heat loss, and debris entry. You should also remove any leaves, twigs, or insects that may fall into your pool as soon as possible.
- Avoid using too many pool chemicals or additives that may affect your water balance or create phosphates, which are nutrients for algae. You should also avoid using algaecides unless necessary, as they may interfere with your chlorine level or cause staining or foaming.
Algae are a common problem for saltwater pools, but they can be easily identified and removed with proper care and maintenance. By following the steps above, you can restore your pool water to its clear and sparkling condition and enjoy your saltwater pool all year round.