I have a sand filter and an in -ground swimming pool. The pool is constantly cloudy.

I use a clarifier and the dirt forms a sediment at the bottom.

Following this I re-connect the pool cleaner and start the pump on filter - the dirt returns to the pool.

If I use the vacuum option and set the pump on waste, some dirty water gets extruded, while most of it returns to the pool.

I have consulted with many pool companies - had the sand changed many times, also had the entire pool filter changed, together with a complete clear - out of the pool and re-start with clear water.

I follow normal backwash and rinse protocols as on your web page.

Unfortunately, none of these have worked and I end up spending too much of money with no satisfaction of use of the pool.

Please help

Thanks for your question

Normally with sand fitlers, when the dirt enters back into the pool it means you have a broken lateral that needs to be replaced.

A couple of other things:

First be sure you're using the correct kind of sand for your sand filter. Normally #20 silica sand; 45 - 55 mm is required for sand filters. Also, check the amount of sand you're using and follow the manufacturer's reccomendations. Check
what is commonly known as the "free-board" or the measurement from the top of the sand to the top of the filters.

The YMCA where I'm the pool operator has
sand filters and the measurement for the free-board is between 12" - 13" for a Triton II commercial sand filter.. Your owner's manual should have that info. If not, you can call the manufacturer.

Changing the sand, if it's the right size, probably will not stop sand from going back into the pool. When you put new sand in you'll get some residual dirt going back into the pool through the returns. This is normal and will decrease as the sand get used.

Be sure you're not using the "RECIRCULATE" setting on your valve when you're vacuuming. This will by-pass all filtration and everything will go back into the pool.

With new sand you probably don't have channeling. This is when the sand is so clogged with dirt, debris, algae, grease, etc... that the water goes down the sides of the filter sand, and not through it.

When you backwash, be sure you're allowing enough time for the water to run clear.

You can go to this link for more info. on cloudy pool water:

Cloudy Pool Water..Treatment..Prevention

When you do have cloudy pool water, it's very important that you get the pool chemicals balanced.

Swimming Pool Chemistry..Care..Maintenance..

Chlorine 1.5 - 3.5ppm
Alkalinity 80 - 100ppm
pH 7.6 - 7.8
Hardness 150 - 250ppm
Cyanuric acid (CYA) 30 - 50ppm

Be sure to have the skimmer(s), bottom drain, and pump basket clean for proper circulation of the water.

Hope this helps and let me know how it turns out for you


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How Long Does It Take A Cloudy Pool To Clear?

by Eric

I opened our pool four days ago and the water is still very cloudy.

The chlorine level is very high and I have been shocking the pool every other day. All other levels are within specs.

I even took a sample to the Lighthouse to confirm I wasn't missing something.

They said it is fine.

I am wondering if my sand filter is not working.

The pool is only two years old so the media should be fine but the pressure on the filter has not changed at all since I started the pump four days ago.


Thanks for the question Eric

There actually could be many reasons why your pool water is still cloudy.

You can go here to see a very long list of them:

Cloudy Pool Water

Normally, a cloudy pool indicates the early stages of an algae growth.

Here are some other good questions that I've answered that are very similar to yours:

Cloudy Pool Water

What Would Make My Swimming Pool Water Get Cloudy

Our Swimming Pool Water Is Slightly Milky? Problems..

The last post is very good. It refers to your cyranuric acid level (CYA). High levels of CYA can cause your pool to be cloudy or milky color.

If your CYA is really high it is making your chlorine ineffective.

The CYA range is 30 - 50ppm. Be sure your pool store tested for that.


You need to keep filtering 24/7 and backwash once per day, just in case it is an algae growth.

If you could give your exact chemical readings; chlorine, pH, alkalinity, CYA, calcium hardness.

It's possible that even by shocking the pool you may not have hit the super chlorination level and that's why the pool is still cloudy.

You always want to wait for 1 full turnover of the water, normally about 8 - 10 hours, then retest after making any other adjustments. This is where patience comes in handy.

Come back with the chemical results and we can go from there.


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Pool Turned Brown After Dosing With Sodiumhypo Chlorite

by Brett
(Bloomsburg Pa. USA)

After opening my pool (approx 50,000 gallons) which was a deep green, we put several 3" chlorine tablets in the skimmer box and was shocked with roughly 10 lbs of non chlorine shock I had left over from last year and my pool quickly became relatively clear. There was still a haze with some visible algae, so the pool was re shocked with Calcium Hypochlorite, and virtually instantly turned chocolate brown. Please advise me as to what I should do to correct this situation.

Hi Brett. I need your complete chemical readings, the actual numbers:

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper) and names of any algaecides you may have used along with clarifiers, phosphate removers, and/or flocs. It makes troubleshooting much easier and the process of clearing up your pool will go much faster.

Next is to check for metals in the water. Are you on city or well water? Even some city water contains metals. If the tests are positive you need to use a metal sequestrant with the ingreident 1-Hydroxyethylidene-1, 1- diphosphonic Acid. Jack's Magic has a good line. Jack's Pink or Purple Stuff is good. Dose your pool per the directions on the bottle.


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