Can Too Much Chlorine Cause Cloudy Water?

Is your pool water looking a little dishwater-esque?

It happens to even the savviest of pool owners, so don’t hit the panic button yet.

It is not unusual to have cloudy water with high chlorine levels in the pool. But while it is possible to have both cloudy water AND high chlorine levels in the pool, the cause of cloudiness is NOT because of high chlorine levels – rather, your pool’s cloudy water is caused by some other underlying issues such as water balance, filtration, algae, or water mold issues. The very first step you need to take in fixing cloudy water is to test your pool water. Once you have your results from your test strip or test kit, read on.

Total chlorine is high & free chlorine is low

If your total chlorine level is high, but your free chlorine is low, that means most of the chlorine you have in your pool is already combined into something called chloramines – combined chlorine is not available to sanitize your water. As a result, you may not have enough active chlorine to keep the water clear. So, this is a situation where your total chlorine is high and your water is cloudy, but it’s not the high chlorine that’s causing the cloudiness; it’s the low free available chlorine level that’s actually making your water murky. In this case, you’ll need to shock your pool to get rid of the combined chlorine and keep the pool clear.

To learn How to Dispose of pool life chlorine tablets, read this article: How to Dispose of pool life chlorine tablets

What if my total chlorine and free chlorine levels are both high?

If your total chlorine level is high, and your free available chlorine level is also high, it’s possible that there’s an excessive amount of chlorinating chemicals in your swimming pool. But it’s not the excessive amounts of free chlorine that are actually causing cloudiness. So, let’s explore some other reasons your pool water can appear murky, and also talk about the action you need to take to fix it – including the “wait and see” approach which, honestly, is like, 75% of pool ownership.

1) Aftershock – Sometimes pool water looks cloudy right after you apply shock granules such as cal-hypo, or liquid shock, but rest assured it’s only temporary. This could be due to a change in water balance – meaning your pool water temporarily goes off balance when adding these products. Sometimes adjusting your total alkalinity and pH to the lower end of the acceptable ranges (Total Alkalinity 60-100 ppm and pH 7.2-7.4) before shocking can help in preventing this from happening.

2) Cooler pool water – In some cases, applying chemicals in granule form in cooler pool water can give the appearance of cloudy water as well – simply because the granules don’t dissolve as quickly in cold water. This is a great time for the ever-popular wait-and-see approach. If cool water is the only problem, cloudiness will clear up swiftly.

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3) High pH, total alkalinity, and calcium hardness – If you have high alkalinity, high pH, and high calcium hardness, the water in your swimming pool may get cloudy. This is because calcium can precipitate out of the solution making the water cloudy.

4) Algae – If your pool water is murky and looking a little too “organic” (read: has a hint of green) you may have too little free available chlorine to sanitize the water and kill the algae, or you may have high cyanuric acid levels that reduce the chlorine effectiveness.

5) Filter issues – A clogged or otherwise improperly working filter can cause your water to become cloudy because it’s not filtering effectively.

6) Low free chlorine – When your free chlorine is low, (regardless of how high your total chlorine is) the absence of free chlorine can turn water cloudy (and likely also exude that ripe, eyeball-burning, waterpark-y smell).

So, what now? How do I fix a cloudy pool?

First, test your pool water so you can get a baseline for the chemical levels in your pool. This will tell you a lot about what could be causing your pool’s cloudiness.

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Test Results: High-free available Chlorine

If your water test shows your free available chlorine level is above 4ppm, wait 24 hours to see if chlorine dissipates and cloudiness clears up. Check the filter to make sure it’s working properly, then add some clarifier and test the water before jumping in (make sure the water is clear).

Test Results: Low Chemical Levels

If your free chlorine level is low, try adding shock first to increase the chlorine level enough to sanitize and clear the water.

If You See Algae

If you see algae, shock the pool using the appropriate dosage for your swimming pool volume (round up if the measurement isn’t exact). Wait 24 hours, then add algaecide directly to your pool water and brush your pool until the algae is gone (when you have algae, brushing daily is important to make sure any shock and algaecide work effectively to destroy the algae).

Keep an Eye On Your Cyanuric Acid (also called CYA)

Also, check and adjust your cyanuric acid to make sure it is not high. The cyanuric acid reduction could only happen by diluting of the pool water with fresh water.

If You Suspect a Filter Issue

One way to figure out if the filter is properly working is to check the back pressure on your filter (pressure gauge). When your filter is running, pressure should climb over time. If your filter isn’t working properly, clean your pool filter using a filter cleaner. If you suspect something’s broken (not clogged), you may have to call in a pool pro to help identify the problem.

If It’s Cold Outside

If you’ve just shocked the pool, and the pool water and outside temperatures are cold, take the wait-and-see approach. The sun should warm up the water and help the chemicals dissipate, clearing up the cloudiness in your water.

Water Balance Issue

Imbalanced water is usually the main cause of water cloudiness followed by filtration issues. If your pH, calcium hardness, and alkalinity levels are high, adjust them to the appropriate levels by first adjusting total alkalinity, then adjusting the pH, and at last adjusting the calcium hardness level.

Can I just go ahead and swim in a cloudy pool?

I mean, what could possibly go wrong?! Honestly, a lot. Many, many things could go wrong if you swim in a cloudy pool. So, DON’T, as in SUPER-DEFINITELY NOT swim in a cloudy pool. Depending on the source of the cloudiness, there could be significant bacteria, a chance of skin and eye irritation or, most importantly, you may not be able to see a struggling swimmer if you can’t see the bottom of the pool.

You are not alone – the unrelenting popularity of trial and error.

We want you to know that you can do this. This whole pool management thing is a lot of trial and error. It’s a lot like parenthood. Consider having a fussy baby: The baby can’t just TELL you what’s standing between him and a good night’s sleep. You’ve got to take his temperature and test a few theories before you land on the right one. (Not to mention, BONUS: Pool ownership comes with a lot more sleep.) Now, the right tools can help you out. Reading articles, watching videos, and testing your pool water with test strips that help inform your next recommended move can save you a lot of time. You’ve got this.

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