Why Does My Pool Keep Turning Cloudy After I Shock It?

Did you shock your pool expecting clear water. Instead, you got a milky and cloudy looking pool? You did what you thought was right and now it looks worse.

At Shasta Pool Supply, our team answers many pool chemical related issues. Our Equipment and Chemical Experts offer years of experience and knowledge. Most situations they have seen before. In most cases, your pool is just in the middle of cleaning.

This article covers what's happening after you shock your pool. We share how long it should take to clear. Also, we highlight when cloudy water stops being normal and starts creating an issue.

Yes, it's very common to see your pool cloudy after shocking it.

What's in your water after shocking it?

• Dead algae cells, broken apart by the chlorine
• Undissolved shock granules that haven't fully dissolved yet
• A temporary pH spike from the shock itself

What is in My Pool that Makes it Cloudy after Shocking It?

Your chlorine shock isn't cleaning your water. It's killing algae that is causing your problems. Dead algae breaks into thousands of tiny particles that are too small for your filter.

Your pool was green and now cloudy. That is a good sign that things are working. Basically, it means the algae is dead and your filter needs time to work.

Your test strip says chlorine is fine. The water still looks cloudy. What is going on?

High pH is one of the things still in there and not filtering out after you shock. A chlorine reading on its own doesn't tell you whether that chlorine is working.

• Calcium hypochlorite granular shock has a pH of around 11 to 12 straight.
• Once your pool's pH climbs above about 7.6, chlorine loses its sanitizing power.
• The chlorine is present. It's just not doing much of anything at that pH.

Can High pH Stop Chlorine from Working After a Shock?

Yes, high pH is an issue. Homeowners then shock again, nothing changes. So, they shock a third time.

Cal-hypo shock is high-pH. Your pool's pH climbs. Now, chlorine stops working against algae and bacteria, until pH comes back down.

The fix is testing pH and alkalinity before you add anything. If pH is above 7.6, bring it down first. Then let the chlorine you've already got do its job. (Poolchemchecker verifies Pool cloudiness after shock)

Arizona water is hard. So, is many other parts of the country. It's just what comes out of the tap here. Hard water applies whether your pool runs on chlorine or an oxygen-based system.

We are finding and seeing some cities where the water, the source water is coming out crazy high. There are some parts of south Buckeye where the TDS is coming out 2200.

Dissolved solids can fall out of solution and settle on the pool floor. They solidify a calcification. A white, gritty layer that often gets mistaken for a stain.Homeowners sometimes acid wash or scrub the floor thinking it's a stain. However, it's just mineral buildup from the source water.

• TDS under 500 ppm — manageable
• TDS between 501 and 1,500 ppm — worth testing regularly
• TDS above 1,500 ppm — difficult water and it's worth asking whether a pool service makes more sense

How Do I Tell the Difference Between Algae Cloudiness and Calcium?

Color and timing are the key differences.

• Algae cloudiness usually comes in gray or a hazy green-white. It follows a shock treatment.
• Calcium cloudiness looks more milky white.
• Algae cloudiness clears as the filter catches up, typically within 24 to 48 hours.
• Calcium cloudiness doesn't clear on its own no matter how long the filter runs.

Give it 24 hours before you start second-guessing the shock treatment.

Keep the Pump and Filter Running 24 Hours

"Keep it running and filter. Within 24 hours, it should start to clean it up, backwash if needed. Clean your filter cartridges, whatever your filter has that you need to do to maintain it." — Dan Panfili, Equipment and Chemical Expert, Shasta Pool Supply

• Pump running continuously
• Some visible improvement by the halfway mark
• A cloudy-to-clear pool usually finishes the job within a day or two

What Should I Do If It's Still Cloudy After 24 Hours?

Don't reach for more shock yet. Check your filter first.

• Backwash a sand or DE filter if the pressure gauge is running high
• Pull and clean cartridge filters
• Keep the pump running another 24 hours before you decide something else is wrong

If you're past 48 hours, test your pH and calcium hardness before adding anything else. A chemistry imbalance won't clear no matter how long the filter runs. Also, dumping in more shock on top of it can make things worse instead of better. (Read More About Chlorine Shock from cpoclass.com)

Most of the time, no. A cloudy pool the day after you shock it is usually proof the shock worked. Give it the 24 hours. Clean the filter if it's overdue.

It becomes a real problem when that cloudiness sticks around past 48 hours. Next, your test strips show high pH or high TDS. At that point, more shock isn't the answer. You have a water chemistry issue.

Your pool burns through chlorine faster than it should. It leaves buildup on your pool floor. You now add chemicals for weeks with no effect.

The first step is testing your water. Test for pH, calcium hardness, chlorine, and TDS.

If your pool's still cloudy and you're not sure why, Shasta Pool Supply can help. Send us a chat or an email and our team will help you get to the bottom of your issue.