Plenty of chlorine pool still green

Plenty of chlorine pool still green.

So you have shocked your swimming pool and the water is still a green colour, so what do you do now?

To ensure you get your swimming pool back into working order there are three main points to consider these are: the correct chemicals, a filtration system and patience to allow the process to give you a clean pool with or without a chemical free swimming pool.

After you carry out the following processes you can then invite your family and friends over and jump in that prefect looking crystal clear swimming pool.

STEP NUMBER ONE: Get your pool ready for shocking and water testing.

First make sure you clean the pool from all phosphates these are twigs, leaves dead insects, dust. Use your pool cleaning tools such asleaf nets etc and a robotic hoover if you have one to clean the bottom of the pool. The pool at this stage may have not been oxidised correctly,ie. Not enough chlorine in the pool. But get all this debris cleaned out of the pool once you proceed to the next stage.


The first thing to do in this section is to test the waters Ph levels however you are not checking the waters chlorine level as you are about to shock the pool. You can check the levels by using either traditional test strips and using the colour to cross reference the alkalinity or acidity of the swimming pool water or you can use some electronic digital floating ph level analysers.

Make sure the ph level is around neutral around 7.0 , if the water is too alkaline ie. Above 7.0 then the swimming pool water after shocking may turn cloudier than normal. If you need to reduce the alkalinity you need to add an acid such as hydrochloric acid to get the swimming pool water balance back to neutral.


As you are using a very toxic chemical you will need to wear appropriate protective clothing. Long sleeved top and trousers and also gloves and protective eye wear. Shocking the pool at a certain time of the day will have an effect on this procedure. Wait until the sun has gone down to shock the pool because sunlight reacts with chlorine so if you shock during the day the chlorine levels will be much lower. However, if you have to shock the pool during the day use a chlorine stabiliser such as cyanuric acid to preserve as much chlorine as possible.

Plenty of chlorine pool still green

Also plan ahead, if you are going the sort of person who likes to invite the neighbors around and , or the family for a swimming pool party this will defiantly affect the pool’s water purity. You will have extras bodies jumping into the water carrying bacteria and the chlorine will have difficulty keeping up. Free chlorine levels drop very quickly with this much usage of the swimming pool. You can bring the level up by shocking the swimming pool.

Weather can have an effect again on deciding when to shock the pool. In hot climates, the weather can change dramatically. You will need to add shock to the water, this will remove contaminants and bring the ph level back up.

Use liquid chlorine to shock the pool and disburse this evenly around the swimming pool then leave to mix with the pool water as long as you can preferably for several hours. At the same time get your pool brush and with some vigour brush the pool thoroughly, and at the same time, you may add some algaecide.


After shocking the pool continue to run your filter for a least two or three days, up to four times a day, and if possible, backwash your filter. If you are using a sand filter continue with the same process and check your filter daily, if you see the psi level increase 5 bar above the normal reading backwash the system. If your system is using a cartridge filter you will need to clean your pool more often. Run the filter twice a day for a minimum of two to three days or until you are happy with the clarity of the pool.


If you have invested in a salt water chlorinator this is still give you the same result. The salt water pool uses a chlorine generator to convert the salt into chlorine. You can then adjust the level of chlorine produced by the generator.

However, the water will still need shocking if used by many people, bad weather etc.


After going through the above procedures you should now have a crystal clear pool.However this will take around one to two days for the chemical treatment in your pool transform the swimming pool water into crystal clear water. You can obviously use a non-chemical solution to a chlorine free swimming pool that will give you just as good as result.

Now you need to do a ph level test on the water and again try to get as close as you can to a 7.0 ph reading. If the reading is ok then backwash your filter once more and you are then ready to jump in your swimming pool.

If for any reason the swimming pool is still green you will, unfortunately, repeat all the above processes until the pool is clear.


If the pool is still green then you may have the Cyanuric acid level too high. This is one of the main courses of people who have green pool after adding the chlorine and following the above procedures and still in the same situation with a green pool.

The Cyanuric Acid  or CYA is an acid that acts as a sunblock for chlorine so it basically lasts longer in the swimming pool water. Too little of the CYA and the chlorine burns off in the sunshine’s rays this leads to a green swimming pool. If you decide to add too much of the Cyanuric Acid then this inhibits the chlorine in it’s function to oxidiser and sanitise the water.

When using the Cyanuric Acid you must measure it carefully. You will need to add to your swimming pool 30 to 50 parts per million ( PPM ). If you take your eye off the ball and start to fill the swimming pool with closer to 100 PPM then you will have to replace the water. You will need to part drain the swimming pool water and refill it.

Plenty of chlorine pool still green

Your maximum Chlorine level should be 7.5% of the CYA reading. If for example the reading is 110 parts per million the chlorine needs to be at 8 parts per million.

So why does Cyanuric Acid get too high?

The answer to this question is that there are basically two types of Chlorine used in swimming pools, stabilised and unstabilized. So the unstabilized is liquid chlorine that is available normally in a bottle and the other is stabilized chlorine that is in tablet form like a dishwasher tablet that contains CYA. When you are shocking the swimming pool water and trying to get rid of that green color water you add more and more tablets and think you are doing the correct thing. STOP, you are actually adding more and more CYA, you are in fact going to get into a situation when the stabiliser will be too high.

In our opinion its best to use liquid Chlorine on a weekly or daily basis for the sanitisation of the pool . If you need to use the stablised Chlorine is great for specific applications but not to be used on a daily or weekly basis.

One last little piece of advice , when using Chlorine it works better at a lower ph. The recommended ph level people use is in the range of 7.2-7.8 , the sweet spot is 7.5. Chlorine is more effective at 7.2 than at 7.8. Your pool will work fine at these levels but over 8.0-8.2 it will not be working efficiently.

That is about it for our advice on using Chlorine and your pool is still green. There are many other websites where you can get more advice on this subject. Thank you for reading our blog post.

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