In a swimming pool or spa, algae are those green, brown, yellow, black, or pinkish slime that resemble fur growing on the steps and in corners — places where circulation may not be optimum.
A great way to determine if algae is present in your pool is by identifying what the pH levels of your water are. If the levels are too high, it's likely that algae could begin to grow. For basic monitoring, you should consider the pH1000 sensor, which is designed to be used with pools.
The most common form of algae in swimming pools is "green" algae. Green algae varies in color from blue-green to yellow-green to dark-green. It can be free floating in the water (turning the water a hazy green) or can cling to the wall-clinging (patches of green).
Algae can be very slippery, causing swimmers to fall resulting in bumps, bruises, cuts and even broken bones. Don't try to swim in a pool that's full of algae. Besides causing injuries, an algae infested pool creates a higher risk of drowning for those who are not expert swimmers or those who fall unconscious.
Small, isolated blooms can be treated locally with granular chlorine or a good quality pool algaecide, followed by a stiff brushing. Algae growing over larger sections of the pool, or suspended in the water will require a strong dose of chlorine pool shock, or granular chlorine, to kill the algae.
You can get rid of algae quickly by vacuuming and brushing your pool, balancing your pool's water chemistry, and then shocking and filtering your pool water. Just be thorough as you clean your pool surfaces. If you leave behind even a small number of algae spores, it won't be long before they regrow and bloom again.
Pool algae can be caused by poor filtration, out-of-balance water, low or inconsistent chlorine levels, or poor water circulation. Green, dark green, yellowish green and blue-green algae are the most common. Green algae are slimy.
A nylon or rubber brush is the correct choice for scrubbing the sides of a soft-sided above-ground pool. A large pool brush makes quick work of the job, but you may need a smaller brush to clean corners. Once the particles have been removed from the sides of the pool, turn your filter back on and agitate the water.
Pool water turns green because of algae in the water. Algae can grow rapidly, particularly when it's warm like Summer, which is why it can surprise you overnight. This generally comes down to an imbalance or lack of chlorine in the water.
While the green algae aren't harmful, the bacteria that feed on the algae can cause issues. When you swim in green water, you expose yourself to algae that host bacteria. Swimming in green water could cause bacterial infections on your skin, and you could get sick if you ingest algae-filled pool water.
The appearance of brown algae on the bottom of the pool is a sign of the beginning of an infestation of mustard algae. This is one of the most difficult types of algae to get rid of, and gets its name from its yellowish-brown color.
A fiberglass pool in its worst condition can be algae-free in 24 hours. For a vinyl liner pool, the process can take 3-4 days. For a concrete pool, this can take a week or more.
In a swimming pool or spa, algae are those green, brown, yellow, black, or pinkish slime that resemble fur growing on the steps and in corners — places where circulation may not be optimum.
A Rule of Thumb
Generally running your pool pump for 12-hours a day is a good option. This is based on the assumption that your average pool pump has a turnover rate of about 8 to 12-hours. That means that the total volume of your pool water will filter through your system 2 to 3 times per 24-hour period.
Baking Soda and Green, Blue, or Yellow Algae
You'll need to use an algaecide to kill the algae and superchlorinate your pool to clear the water. After this treatment, test your pH and alkalinity and add baking soda to raise alkalinity to at least 100 ppm and pH to between 7.2 and 7.8.
All you need to do is bypass the filter and pool vacuum for algae to the waste. However, this can only work if you have a multiport system or a waste line system in your cartridge filter. Vacuum the pool to waste after you have set up the waste, and the debris and algae will get out of your pool.
Grab a brush and some baking soda. Bicarbonate, the active ingredient in baking soda, is an effective spot treatment to help kill the algae and loosen it from the wall. Make sure you really get every last particle free; black algae has particularly long and stubborn roots which makes it a persistent strand.
So if the pool water isn't cloudy and the 'dirt' is clinging to the walls after brushing, the problem is likely be yellow/mustard algae. Yellow/ Mustard algae is very resistant to even high chlorine levels and will grow and thrive in a chemically well-balanced pool.
The only thing that kills algae is CHLORINE (or your sanitizing product, or one of the copper-based algaecides on the market). You need to raise the level of your chlorine – shock the pool – and maintain that high level until all the algae is dead. This may take 3 to 4 days. RUN THE FILTER 24 HOURS A DAY.
However, although the black algae itself won't cause illness, it can attract insects or harbor organisms or harmful bacteria like E. coli, which can make swimmers sick. It's best to avoid swimming in a pool with black algae until you've eradicated it.
Mustard algae is yellowish-green in color and often looks like dirt or sand on the bottom or sides of the pool. It brushes away very easily, but returns quickly. If left untreated, it can turn the entire pool a pea-green color in a very short time.