Boost any residual chlorine by adding a quality pool shock product according to label directions. Use a pool brush to vigorously scrub the surfaces where the algae has grown. Use a vacuum or backwash the pool to remove the dead algae. Apply a mustard algaecide following the label directions.
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.
When the levels are properly balanced, chlorine will keep the algae at bay, but the water will slowly begin to turn green as the algae take over if there's not enough. 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.
You normally need 6 quarts of bleach per 10,000 gallons of water, so to kill algae, you might want to increase this to 8 quarts ( 2 gallons) per 10,000 gallons. If the pool water is very green and cloudy, consider doubling the basic dosage. Just remember to stay out of the water until the chlorine drops to safe levels.
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.
You should start seeing a transformation after 24 hours. If you have green pool water after shock, it is imperative to think about your water and pool safety. Hence, don't use the pool after 24 hours.
You cannot overshock a swimming pool or add too much. Adding too much shock or overshocking your pool will kill off algae. The negative of adding too much shock is it will upset the chemical balance of your pool.
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.
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.
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.
But is it safe to swim in a pool with algae? Whether mild or severe, it isn't recommended. Significant amounts of swimming pool algae welcome a breeding ground of harmful bacteria that feed on algae. These bacteria pose health risks to swimmers, most commonly resulting in a skin rash.
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.
You can also simply add more chlorine, and pouring household bleach into the pool is one way to do this. Be sure the pH is in the proper range -- between 7.2 and 7.8 -- and add the bleach in the early evening to avoid having most of it degraded by sunlight.
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.
Use chlorine as your go-to algae killer.
When your pool water is green or contains visible algae clumps, your pool does not have enough chlorine. "Shocking" the pool with a large dose of chlorine is the most effective way to kill the existing algae and bring your pool back to sanitary conditions.
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 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.
It's pretty tough to over-shock your pool; shocking your pool two days in a row with the proper dosage for your pool volume shouldn't be a problem – and in fact, is sometimes even needed to rid your pool of algae and other contaminants.