Green water indicates algae bloom, but not only. It is usually due to a chemical imbalance or a lack of disinfection. This may be linked to stabilizer saturation. Discover more about this phenomenon in our article.

Solve That Problem ASAP: Our 5 Tips

1. Make sure the filtration system is working properly

When the water no longer enters the skimmer, it means that air has entered the filtration and the pump could not work properly. To solve this problem, here is the procedure to follow:

• Return water to the pool;
• Close the skimmer valve and open the bottom drain to prevent air from entering the filtration. ;
• Check that the filtration system is clean and in good condition. A dirty filter or one in poor condition will not allow the proper filtration of the water and can feed the proliferation of algae.

For sand filters, carry out a backwash (counter-washing) directly to the drain. If it is a cartridge filter, consider cleaning it or replacing it with a new one.

2. Check stabilizer levels

The misuse of stabilizer can cause green water problems. It is therefore essential to check that the water is not saturated with stabilizer because it cancels out the disinfectant effect of chlorine.

The ideal level of stabilizer is between 30 and 70 ppm. Salt water pools should be kept between 50 - 70 ppm. 

3. Check/Balance the pH level

High pH negates the disinfectant power of chlorine in the water and allows algae to grow. You should thus ensure that the pH of the pool water is between 7.2 and 7.4 before adding any other chemical.Here is how to measure the pH of water.

4. Carry out a chlorine shock treatment

When the pH is OK, we advise you to carry out a treatment with shock chlorine powder. This will quickly raise the chlorine level in the water (and therefore its disinfection capacity).

iopool recommends between 150 and 200gr of shock chlorine per 10m³ of water.

5. Use an anti-algae and flocculant

In case of stubborn algae, there are many anti-algae or algaecide products on the market that can be used in addition to shock chlorine. Follow the dosages recommended by the suppliers.

Note that he flocculant quickly improves the quality of filtration and eliminate dead algae residues in suspension.

How to Prevent Green Water Problems?

Problems can be prevented by checking:

• the state of cleanliness of your filtration system;
• the chemical balance of the water in your swimming pool.

☀️Under hot temperatures, bacteria developent is even quicker. Keep an eye on the pH and disinfection potential of the water.

Advice from Sébastien, our pool expert:

The use of a connected monitor like EcO allows to prevent chemical imbalance. And, as the saying goes, prevention is better than cure!