One of the main reasons you need to shock your pool is to get rid of that ugly green color that is often a result of algae growth. Therefore, it can be pretty frustrating to find that the pool is still green after spending several hours shocking it and investing a lot of money on pool shock.
However, if the pool is still green, this does not necessarily mean that the shock did not work. Several reasons can cause this issue, and it is essential to know them and the possible solution as this will help bring back the clear water you desire.
6 Reasons Your Pool is Still Green After Shock
1. You Did Not Use the Proper Amount of Shock
In most instances, you need to add at least 10 times the amount of combined chlorine in the pool. A typical swimming pool will have between 1 and 3 ppm chlorine, and so for effective sanitization, you need to get the level to at least 10 ppm.
Besides getting the free chlorine level to 10 ppm, you have to sustain it for several hours for effective pool shock. It can be hard to achieve when using certain types like calcium hypochlorite as it breaks down quickly under the sun, given that it does not have a stabilizer.
That said, it is crucial to make sure you get your calculations right so you know the right amount of pool shock to use. Additionally, several rounds of shocking are necessary when dealing with a green pool. Also, use calcium hypochlorite with a stabilizer for the best outcomes.
2. Inefficient Filtration System
Your pool filtration system plays a crucial role, and it will be an integral element when clearing out green water. Therefore, if it is not working well, you might still end up with green water even after several rounds of pool shock.
Remember that the filtration system ensures the shock gets to every part of the pool, so if it does not do its job, some of the water will not get the treatment.
An easy fix for this is to give the filtration system quick maintenance before you start shocking. In most cases, this will include checking that everything is working correctly, flushing and cleaning the system, and replacing filters.
3. Pool Chemistry is Off Balance
If you notice that your pool water went back to being green after shocking it, this can be a sign that the overall pool chemistry is still off.
When the pH, alkalinity, chlorine level, pool stabilizer (cyanuric acid) are off-balance, it will be hard to keep the water clear no matter how often you shock.
Therefore, even as you add shock, make sure the pH is at the 7.2 to 7.8 optimal level, alkalinity is between 80 and 120 ppm, chlorine level is 1 to 3 ppm, and the cyanuric acid level does not exceed 50 ppm.
4. The Source is Not Algae
Sometimes the only reason your pool water is still green after shocking is because you were treating the wrong thing. Although algae growth is the primary source of green pool water, it is not the only one.
Other things like high copper content and pollen can leave you with a green pool. If the water has too much copper, pool shock oxidizes it and turns the water green. However, this is an easy issue to fix as you only need to add more calcium to increase water hardness.
On the other hand, if there is a lot of green pollen from trees and grass in the pool, the water also changes color. The best and quickest fix for this issue is to skim, filter, and brush the pool regularly.
5. You Did Not Give it a Thorough Scrub
You might spend a lot of time and use extra effort to ensure you get the shocking process right but forget to give the pool a thorough scrub.
If you do not scrub the pool wall and floor, some of the stuff causing your water to turn green such as algae and pollen, will still have a place to hide. Therefore, your water might remain green after shocking.
A good pool brush will be handy when dealing with this problem. However, when choosing one, you should make sure the bristles match the pool type you have. For example, if you have a tile pool finish, you need a brush with soft bristles.
6. You Skipped Clarifier/Pool Flocculants
Pool clarifiers and flocculants are very useful when trying to clear up green water. They help by binding to the algae and other impurities that might be causing the water to turn green. These impurities then float on the surface or fall to the pool’s bottom to make vacuuming or skimming easy.
Although they might not always seem necessary, failing to use these products can sometimes be the only reason your pool shock does not seems effective at clearing the green water. Therefore, it is essential to remember to use them as you shock the pool water.
It can be disheartening to find that your water still looks green after all the energy and time you spend shocking. However, if you can identify the reason, the problem is easy to fix.
Lastly, if everything you do still does not solve the problem, the only other solution might be to drain the pool, scrub it and clean up all the fixtures before refilling it again.