What Causes Pool Water Turn Green & What Can You Do To Fix It?

Stepping out for a quick dip in the pool only to find that the pool water has turned cloudy and green can be nothing short of a nightmare. 

Instead of sparkling blue and clean water, you find yourself looking down at a swamp. And all of this can happen overnight, especially, in the warm summer months.

What Causes Pool Water To Turn Green?

So, what causes a pool to turn green? This rapid green invasion is the result of algae blooms in pool water. The rapid growth of algae is usually due to an imbalance in pH and chlorine levels of pool water. 

This is why checking chlorine levels in pool water regularly is so important. A lack of chlorine in the water (anything below 1 ppm) can result in rapid algae growth turning your pool into an uninviting green color.

The Importance Of Healthy & Balanced Pool Water Chemistry

If you are using a swimming pool test kit to measure Chlorine and pH levels the ideal readings during testing should be as follows:

• The ideal pH level should be around 7.6-7.8
• Ideal chlorine levels should be between 2-3 ppm

If these are not the readings you are measuring then you need to balance the pool water chemistry. In order to increase pH levels add sodium carbonate. If pH levels are too high bring it down by using sodium bisulfate. 

However, before adding any strong chemicals it is always best practice to scrub the walls and floor of your swimming pool using a pool brush with tough bristles. Algae likes to cling on to pool surfaces so scrubbing the walls and the floor can help dislodge algae and break it apart making it easier for the chemicals to do their work. 

Also, when adding chemicals make sure to switch on your pool pump to allow the chemicals to efficiently circulate throughout the pool. This would lead to much better results.

What If Chlorine Levels Are High But Water Is Still Green?

What if you have shocked your pool and balanced the chlorine and pH levels to what they should be and yet you still find your pool looking like a swamp? In such a case, it is quite likely that your filter isn’t functioning properly or is clogged.

If you have a sand filter it will take a lot longer to clean up the algae. A decent cartridge filter will do the job faster but the cartridges will have to be repeatedly rinsed and cleaned, every day, to ensure that leaves, sticks, algae, and debris don’t clog or damage the filter.

Using heavy doses of the wrong chemicals is another reason as to why your pool water is still green despite high chlorine levels and all your attempts at balancing pool chemistry. 

The prolonged use of stabilizer chlorine tablets can “lock-up” free-roaming chlorine molecules, thereby changing its chemical form. As a result, you could be seeing high chlorine levels on your pool test kit but that chlorine is not killing algae as its stabilizer levels are too high.

There is no chemical solution when it comes to lowering stabilizer levels. The only thing you can do is dilute the existing pool water by adding fresh water to it. 

Another Reason As To Why Your Pool Water Can Continue To Remain Green

Close proximity to sources of phosphates could be another reason as to why your pool water refuses to go back to its sparkling blue-self. Phosphate levels can build up in your pool water from leaves, organic debris, and fertilizer.

Since algae thrive by feeding on phosphate you can have what may seem like a real problem on your hand. However, they are several products that can remove phosphate from pool water and in doing so kill the algae food supply. No food source means the algae will soon die and float to the bottom of the pool where its remnants can be vacuumed up. 

Adding a flocculent during the vacuuming process can help make the job a tad easier. Flocculent binds algae particles together making it a lot easier for you to vacuum saving time and energy.

It is also recommended that you cover up your pool after use if you live in an area with lots of trees and greenery. A protective pool cover can help prevent organic debris from finding its way into your pool.

Shocking Your Pool – Is It Necessary?

If chlorine levels are low in your pool water and it has turned green, using pool shock treatments can be the fastest and most effective way to sanitize the pool and devoid it of any algae.

Choose a concentrated shock solution that has at least 70% available chlorine. Always read the instructions and directions on the shock package. Make sure to measure the amount of shock carefully based on the volume of water in your pool.

Depending on how severe the algae growth is you might have to shock treat your pool more than once to ensure that there are no more algae blooms.

When adding shock treatment you pool water may turn even cloudier and dirtier than it was before. But that isn’t a sign of concern. Keep the pump and the filter running and soon you will see water clarity return.

Pool shocking is certainly necessary when faced with the prospect of an algae bloom. It can be very effective, if done right, and can make quick work of an otherwise difficult problem. 

Key Reminders

If you are a new pool owner faced with the prospect of cleaning up an algae infested pool can seem overwhelming. However, it is important to remember that algae blooms are quite common, especially, in the summer months and there are many ways of effectively treating them. 

Always ensure that you first start the treatment process by testing your pool water. The results can tell you a lot as to the reasons behind this ugly green mess. 

As soon as you have the results, take action! The longer you wait the faster the algae will grow and the longer and harder it would be to get rid off.

By following these directions and tips we hope that all of us pool owners can protect ourselves this summer from the menacing green algae and keep our pool waters blue and sparkling clean!