To kill green algae, add a chlorine-based shock to the pool. Give the pool a thorough brushing and run your filter to remove the dead algae from the water. After you've killed the algae, you'll need to add a clarifying product (flocculant) that will cause the skeletal remains to sink to the bottom.
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.
Green algae, unlike its black counterpart, is a true algae; it isn't resistant to chlorine, so you can control it by shocking the pool. If you don't want to spend a lot of money on expensive pool chemicals, you can shock with household bleach.
Algae will remain in your pool after shock if you've had insufficient chlorine and an overabundance of metal elements in the pool water. Therefore, to start the cleaning process. Remove all the debris from the pool with a leaf net and then let the smaller dirt fragments settle.
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.
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.
What's important for you to know: You shouldn't swim in a pool that's green until you test the chemical levels, like the officials in Rio did before the diving event began. It's the balance of things like chlorine, pH, and alkalinity in a pool that keeps it sterilized.
Too High Cyanuric Acid Level: This is probably the NUMBER ONE reason people have green pools after adding chlorine.
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.
The solution to maintaining a clear pool is to use readily available liquid bleach as your chlorine source. Chlorine bleach, as discussed above, is not bound to a stabilizer, so when you add chlorine bleach to the pool, it will go right to work killing microbes and sanitizing.
Calculate the amount of bleach you need based on the fact that 1 gallon will raise the free chlorine level of 30,000 gallons of water by 2 ppm. If you need to mildly shock a 30,000-gallon pool by raising the free chlorine concentration to 5 ppm, you need 2.5 gallons of bleach. To raise it to 10 ppm, you need 5 gallons.
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.
Shock Your Pool
To eliminate any contaminants or chloramines in your cloudy pool water, add a high dose of chlorine by shocking your pool. If the cloudy water in your pool is due to a pool algae bloom, you'll have to double or triple shock depending on the type of algae you have.
The pool turned green from copper, not algae
Think of the Statue of Liberty. It is made of copper, and has turned green over time through oxidation.
Use a vacuum or backwash the pool to remove the dead algae. Apply a mustard algaecide following the label directions. Allow the water to circulate for 24 hours. Use a pool vacuum or backwash the pool again to remove the remaining dead algae.
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.
It's important to note that you should not try to vacuum green pool water until you have removed any and all organic debris using a pool net, and have added the proper chemicals to the water, and done proper brushing so that the green algae has visibly settled to the bottom of your swimming pool.
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.
Baking soda is safe and straightforward to use, while also providing your pool with a clean, clear, sparkling water that is pleasant to swim in. Baking soda does not sting the eyes; neither can it cause drying of the skin.