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.
The free chlorine levels might be low.
But be careful—adding too much chlorine in pool water can cause those metals to oxidize and turn the pool a different shade of green.
The fastest way to clean a green pool is by using pool chemicals and your pool filter. This process usually takes around 4-5 days but you will start noticing a major improvement after 24 hours.
If your pool is green but chlorine is high, it's possible that you aren't running the pool's filter often enough or for long enough to filter out algae and bacteria. In spring and summer, when it's warm outside, pools should be filtered for eight hours a day, regardless of whether the pool is in active use.
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.
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.
In theory, if you have a cloudy swimming pool, you can add chlorine to “shock it” and clear things up. Chlorine will get the job done. But, the amounts may vary and you may have to really pound the pool with chlorine to get the water totally clear.
Pools can immediately turn green after shocking when they have metals like copper in the water. These metals oxidise when exposed to high levels of chlorine which makes the pool water turn green. Adding a metal control product such as Zodiac Metal Remover will help to restore the pool water.
The most common reason pool water turns green is due to algae growing in the water. Algae can grow rapidly, particularly in hot weather, which is why it can surprise you overnight during the warmer months. This generally comes down to an imbalance or lack of chlorine in the water.
ADD POOL CLARIFIER
The change in your pool water colour means that you have successfully eliminated the algae and can now clean it out of your pool. If your water is still green, wait another 24 hours and redo the steps from Days 1 and 2.
While shocking and adding algaecide is effective in getting rid of algae, it should not be done together. This is because when you mix chlorine and algaecide together, it renders both of them useless. Hence, you should first shock the pool and wait for the chlorine levels to fall below 5 PPM.
A pool turns green when there is algae in the water. There are several reasons why algae could grow, but it is most commonly caused by prolonged exposure to the sun, rain and temperature spikes. These factors affect the chemical balance of the pool and result in the pool turning cloudy and/or green.
Baking soda can work wonders in a pool. Baking soda can: Help to clear cloudy water and restore the sparkle. Spot-treat algae.
In a nutshell, pool clarifiers are “mild” versions of flocculants. They're great for mildly cloudy pool or if you have a silt problem that your filters just can't catch. What they do is they bind to these tiny particles to increase their size, allowing your pool filter to catch them.
Once the clarifier has been added to your pool, turn on the pool filter and run it 24/7 until the cloudiness is gone. This can take two to three days, but swimming in the pool at this time is safe after about 20 minutes.
Clorox itself recommends using between 100 and 200 ounces of regular-strength bleach per 10,000 gallons of pool water -- one gallon is 128 ounces, and many bottles of bleach are available in one-gallon or half-gallon sizes. Pool professionals tend to recommend more conservative amounts of bleach.
Just like you run vinegar through your coffee pot to get rid of calcium buildup, white vinegar can wipe away this eyesore in your pool. Mix a 50/50 solution of vinegar and water, dip a sponge or soft cloth into it, and scrub that residue away.
It is important to know what exactly bleach is before you put it in your pool. Household bleach, Clorox and liquid chlorine can all be used to sanitize a pool. They are all types of chlorine. Household bleaches such as Clorox usually contain about 5-6% available chlorine, about half that of pool liquid chlorine.
Algaecide will be able to help you clear cloudy green pool water such as this. Algaecide, to put it simply, is a pool chemical that can kill algae or prevent it from growing in your pool.
The presence of too much algaecide can lead to a foamy pool water. Small bubbles will begin to be produced as the water is pushed through the return jet and back into the pool. Do not confuse these bubbles and foam with another common problem, which is air in your pool lines.
Light Green or Teal Pool Water:
In this case, you should double shock your swimming pool water. To double shock, you will need to add 2 pounds for every 10,000 gallons of water. For instance, if you pool is 20,000 gallons, you will add 4 pounds of shock.