How to Lower Chlorine in a Pool
Understand "chlorine smell" and stinging eyes., Use a pool test kit., Remove chlorine sources., Uncover outdoor pools., Swim while chlorine levels are still at safe levels., Replace some of the pool water., Test regularly.
Step-by-Step Guide
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Step 1: Understand "chlorine smell" and stinging eyes.
Many people think that a chemical smell or stinging eyes are signs of chlorine.
In fact, these usually show up after chlorine has broken down into other chemicals.
The right response is usually to raise chlorine with a shock treatment.Better yet, use a test kit to get an accurate read of the chlorine, as described below. -
Step 2: Use a pool test kit.
If you haven't already, test the chlorine levels using a test kit from a pool supply store.Make sure the test kit measures both free available chlorine (FAC) and total chlorine.As a general rule, free available chlorine (FAC) should be between 1 and 3 ppm.Total chlorine should be no more than
0.2 ppm higher than FAC.
Your local health codes may have different requirements.If your pool also uses ozone or UV disinfection, FAC can be reduced as low as
0.5 ppm., If the chlorine levels are only slightly high (about 4–5ppm), chemicals are usually not necessary.
Just stop adding chlorine to the pool, and the problem will likely solve itself.To stop adding chlorine, turn off the chlorinator, chlorine feeder, or salt water chlorine generator; take the chlorine tablet out of the pool skimmer; or remove the chlorine floater.
If you are not sure which system the pool uses, ask the manager or owner. , Ultraviolet light from the sun rapidly breaks down chlorine.
A single cloudless afternoon can remove 90% of your pool's chlorine, as long as you have removed all chlorine sources.Ultraviolet lamps are not usually a good replacement for this step.
See the UV method below for more information. , Swimming helps lower chlorine, but only try this if chlorine is at slightly high (4 ppm).
Experts disagree on how much chlorine is dangerous to swimmers.
Public pools often shut down at 10ppm, while some pools use a 5ppm limit to be extra safe.Do not swim if your pool test had additional unexpected results, such as the wrong pH or alkalinity.
Do not swim if you smell a strong "chlorine" smell (and the chlorine test gave high results).
This smell is actually from irritating substances called chloramines.Chlorine affects the lungs.
It is more dangerous in poorly ventilated areas, and if the swimmers have breathing problems., This is an expensive, slow option, but it will dilute the chlorine.
Drain and replace about ⅓ to ½ of the pool.
After refilling, your pool may take a long time to return to normal chlorine levels and pH.If you have a filter has a backwash option, this is the fastest way to (partially) drain your pool. , Repeat the pool test once or twice a day, or every couple hours if the pool is still in use.
If chlorine levels do not decrease within a couple days, try one of the methods below.
See Tips below for guidelines on other test results, such as pH or cyanuric acid.
If your test results fall outside these guidelines and do not correct themselves soon, you may need to hire a professional. -
Step 3: Remove chlorine sources.
-
Step 4: Uncover outdoor pools.
-
Step 5: Swim while chlorine levels are still at safe levels.
-
Step 6: Replace some of the pool water.
-
Step 7: Test regularly.
Detailed Guide
Many people think that a chemical smell or stinging eyes are signs of chlorine.
In fact, these usually show up after chlorine has broken down into other chemicals.
The right response is usually to raise chlorine with a shock treatment.Better yet, use a test kit to get an accurate read of the chlorine, as described below.
If you haven't already, test the chlorine levels using a test kit from a pool supply store.Make sure the test kit measures both free available chlorine (FAC) and total chlorine.As a general rule, free available chlorine (FAC) should be between 1 and 3 ppm.Total chlorine should be no more than
0.2 ppm higher than FAC.
Your local health codes may have different requirements.If your pool also uses ozone or UV disinfection, FAC can be reduced as low as
0.5 ppm., If the chlorine levels are only slightly high (about 4–5ppm), chemicals are usually not necessary.
Just stop adding chlorine to the pool, and the problem will likely solve itself.To stop adding chlorine, turn off the chlorinator, chlorine feeder, or salt water chlorine generator; take the chlorine tablet out of the pool skimmer; or remove the chlorine floater.
If you are not sure which system the pool uses, ask the manager or owner. , Ultraviolet light from the sun rapidly breaks down chlorine.
A single cloudless afternoon can remove 90% of your pool's chlorine, as long as you have removed all chlorine sources.Ultraviolet lamps are not usually a good replacement for this step.
See the UV method below for more information. , Swimming helps lower chlorine, but only try this if chlorine is at slightly high (4 ppm).
Experts disagree on how much chlorine is dangerous to swimmers.
Public pools often shut down at 10ppm, while some pools use a 5ppm limit to be extra safe.Do not swim if your pool test had additional unexpected results, such as the wrong pH or alkalinity.
Do not swim if you smell a strong "chlorine" smell (and the chlorine test gave high results).
This smell is actually from irritating substances called chloramines.Chlorine affects the lungs.
It is more dangerous in poorly ventilated areas, and if the swimmers have breathing problems., This is an expensive, slow option, but it will dilute the chlorine.
Drain and replace about ⅓ to ½ of the pool.
After refilling, your pool may take a long time to return to normal chlorine levels and pH.If you have a filter has a backwash option, this is the fastest way to (partially) drain your pool. , Repeat the pool test once or twice a day, or every couple hours if the pool is still in use.
If chlorine levels do not decrease within a couple days, try one of the methods below.
See Tips below for guidelines on other test results, such as pH or cyanuric acid.
If your test results fall outside these guidelines and do not correct themselves soon, you may need to hire a professional.
About the Author
Anna Allen
Professional writer focused on creating easy-to-follow pet care tutorials.
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