Milky Pool Water

by JC

Last week my pool was clear but the readings were FC 0, Ph 7.2,CH 332,TA 17, CYA 0. I have an inground 20x40 vinyl liner pool. Per store recs, I added 48 pounds of bicarb and 7 pounds of CYA. I also shocked the pool with 3lbs of Cal hypo 73. I added the bicarb all at once and a few hours later added the stabilizer, Since then the pool has become cloudy and increasing to milky.

I have run the sand filter 24/7, and have been backwashing twice per day. earlier this week,Taylor-2006 tests showed everything off the charts especially Ta and PH, so I added 32oz of Muriatic acid and shocked again the next day. No changes to the appearance.

Pool store numbers yesterday were FC 7.4,CC 0 Ph 7.2, TA 17, CH 225, CYA 9. They told me the numbers don't make sense and do nothing for a day and re-test.


Thanks for the question JC and the readings

There are variations with pool sizes of 20 X 40, but I'll go the middle route and say yours is 27,000 gallons.

You're right that the numbers don't make sense with the chemicals that were added. 48 lbs. of bicarb will increase a 50,000 gallon pool 60 - 70ppm. But it had no change in yours, either the pH or alkalinity? And the CH went down from 332 to 225 without a water change? Either the tests were done improperly or something else had to have happened that influence the outcome.

If you could keep filtering, backwashing, and give me a new set of tests in 24 hours, it would help. As it is right now the pH and CH are fine so don't add any calcium or baking soda. No pH or Alkalinity Up until the tests come back. And no acid. None.

The CYA is a bit low at 9ppm. It needs to be between 30 - 50ppm. You should shock with Dichlor chlorine. This is a stabilized form of chlorine. Once you reach the 30 - 35ppm mark, stop with Dichlor and go to regular liquid chlorine.

Be careful when using Dichlor as it can get out of hand quickly. For every 10ppm of chlorine added with Dichlor, you'll raise the CYA by 9ppm. For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm. 1 1/3lbs. of Dichlor per 10,000 gallons for shock. This will raise the CYA by 9ppm.

Start with 7lbs. of Dichlor. Broadcast it around the perimeter of the pool with the pump on. Brush very well, filter for 8 - 10 hours, then retest the CYA. Don't test too soon. You need one full turnover of the water before retesting. Don't get any of the expensive "conditioner" CYA products. Use simple Dichlor.

Calcium hypo, chlorine granules, have a pH of 12 so if you shock using granules, you're going to be increase the calcium hardness and the pH. Use liquid chlorine instead for weekly maintenance.

You need to get the alkalinity up between 80 - 100ppm. You can accomplish this by using baking soda. No need for expensive Alkalinity Up stuff because it's the same thing, only 5 times more expensive. Get baking soda from your grocery store. Again, don't do this just yet. Shock the pool with Dichlor, then retest and give me those numbers.

Pool Alkalinity

Total Alkalinity

Your pool could be cloudy because of the 48 lbs. of baking soda, or it could be an early sign of algae. It's hard to tell at this time. Because the CYA is low it's rendering the chlorine ineffective. That's why you need to get the CYA in line.

Cloudy Pool Water

So, the thing you should concern yourself with right now is getting the CYA up to 30 - 35ppm using Dichlor then retesting after 8 - 10 hours of filtering. Keep the filter on, backwash, retest, and let me know the latest results. Remember, no baking soda, pH or alkalinity anything, or acid for now. Take your own tests and match that with the pool store's tests.

Hope this helps and be sure to let me know how it turns out.


Comment By Carlos Barra
Date: June 8, 2012

Robert, thanks for your reply. I will follow your advice. I need to clarify that the 2 pool store readings were from different stores. I did not want to go back to the first, since I felt they gave me the wrong advice.

Also I was backwashing frequently without the pressure going up. Should I wait till the pressure goes up?

When I brush the floor or the walk in steps a white powder rises up. my polaris 360 cleaner has white dust build up on it after it dried off. Should I continue to shock with the free chlorine levels that high?

Comment By Robert
Date: June 8, 2012

The powder you're seeing is probably from the calcium hypo. Calcium is the binding agent for granular chlorine. It doesn't dissolve and sinks to the bottom. You'll need to vacuum it up. I used 20 - 25lbs. to shock the Y pool, then went back the next day and spent another 2 - 3 hours vacuuming.

One thing you can do is turn off the pump. Very gently and slowly sweep the sides and allow the calcium to settle, an hour or two, then turn the pump back on and vacuum. If you try to sweep with the pump on, the calcium will hit the water from the returns and blow it through the pool. Little trick I learned from vacuuming pool in Arizona after their massive wind and dust storms.

If you do have algae you'll want to switch to regular liquid chlorine. Get AND keep the chlorine level up to 12ppm if you have algae. Test and adjust morning and evening. Again, it's hard to tell whether you have an early algae bloom or if it's the bicarb that was added. Anything over 12 - 15ppm chlorine and you're just wasting money and chemicals.

You can allow the filter to go for a couple of days, then check the pressure and backwash. If the water isn't dirty, allow for longer times between backwashing. If the water runs clear between frequent backwashes, you're wasting water.

Like my last post said, get the CYA up to 30 - 35ppm. This is important because it will render your chlorine the most effective for weekly maintenance at this level. 30 - 50ppm is optimal range.

Remember that if the pool is cloudy because of the bicarb, a clarifier won't help so don't waste your money on that.

Hope this helps and be sure to let me know how it turns out.


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Aug 16, 2016
White powder in water
by: Mike

I have had an outdoor freshwater pool working fine for the last 3 years in Spain, we treat the water with acid and chlorine to maintain the balances as we are in an extremely high alkaline area.

Over the last 4 months we are getting a white residue on the pool floor, walls and skimmer flaps. So much that we recently removed 2 gallon buckets of it with a jet washer.

I have applied hydrochloric acid to it but got no reaction whatsoever so it is not lime scale. it is a fine white powder when dried out. The pool is brilliantly clean and sparkling. The walls of the pool seem to have a fine layer of hair on it until it is wiped and then it turns to a fine cloud and settles on the bottom.

Neighbours pools fed from the same water supply do not have a problem. Any help would be appreciated. Thanks Mike

Jul 09, 2015
I Need Cloudy Pool Water Help
by: Anita

I have opened the poor for already three weeks, however, the pool still very cloudy. I have tested water as follow:


I ADDED TOO MUCH CHLORINE THREE DAYS AGO BY MISTAKE. I HAVE TRIED MANY POOL SUPPLIES FOR ADVICE, BUT THE WATER STILL NO CHANGE. I have been watching your tube video and thinking you are very professional for dealing with pool issue. I really need help. Please help! I think that Canada has no good pool guy here.

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