Causes and cures for cloudy swimming pool water.
Milky pool water, white, pink, brown, purple, black cloudy water.


Postby Smitty » Thu 19 Apr, 2012 17:21

You need to change your sand in your filter and check the manifold for a crack(the pipe that run through the middle of filter



Postby teen » Sun 01 Jul, 2012 14:17

guess im not going to use the floc, my pool is cloudy and have tryed EVERYTHING?? its been a week of backwashing,vacuming,and still cloudy.. not really sure now what to use? good luck with your pool
Ray & Cheryl


Postby Ray & Cheryl » Wed 04 Jul, 2012 11:50

Cloudy Pool Problem Solved With Quick Drain
This has been the most discouraging pool opening ever!!!!!!!! We have had a pool since 1985, we presently have a Jacuzzi pump and filter . This year…our pool water has been SO cloudy that we could NOT see the top rung of the ladder….let alone the bottom of the pool. The chemical readings were fine, we even went as far as changing the filter sand and still no good results, it seemed no matter what we did ended at a dead end. Then we got this bright idea to shut the pool down for one night, well would you believe it in the morning….everything had settled to the bottom….CLEAR….we could see the pool bottom the ladder everything!!!!! At this point it wasn’t hard to figure out what was going on, by keeping the pool running…this very light…almost like a talcum powder was forced to circulate or crawl if you will through the water keeping the pool cloudy, with the pool off for several hours it had a chance to settle to the bottom in pockets all over…NOW TO GET RID OF IT!!!! We used this new idea called “QUICK DRAIN” (check it out @ or With this new amazing device we were able to very quickly vacuum (with filter on waste) all of the pollutant from the pool. In order to completely eradicate the pollutant we knew there was going to be a good amount of water loss meaning the pool water level would probably need to go down below the skimmer also meaning that the pump would no longer be able to run. Thanks to Quick Drain which allows you to continue vacuuming with the water level BELOW the skimmer we didn’t need to shut the pool down. Once finished vacuuming with the filter dial back in the filter position we left Quick Drain inserted in the skimmer to continue recirculating the water until (with the help of a garden hose) it regained its original depth @ the skimmer, this also allowed us to continue enjoying our pool while Quick Drain was doing the work…. “QUICK DRAIN”…an amazing product
yurm om


Postby yurm om » Sun 05 Aug, 2012 16:46

What a dumb b.i.t.c.h. ^


Postby Guest » Mon 06 Aug, 2012 07:54

First take a water sample to a reputable pool store they usually do it for free and tell them you added Floc
I flocked mine about 20 years ago and hope I never have to again
It is a long process that way because once the particles drop to the bottom and you start to sweep
the fine lightweight partials start to float making it impossible to see again and again. There will be a product the pool place will suggest that will catch the particals and bring them to the top and out the skimmer
so you can keep your filter running also this way you can swim which also helps gets the
particles up and out.
Deb K


Postby Deb K » Mon 06 Aug, 2012 15:43

I have used flocculant before. I found key points were:

Use correct amount
Recirculate water for 2-3 hours (RECIRCULATE so floc does not travel through filter)
Turn pump off until everything drops to bottom (this may be over 24 hours)
Vacuum to waste

You really don't want the flocculant in your sand filter. Good luck all. Floc is a tedious bitch but it works.


Postby mark045 » Sat 18 Aug, 2012 01:46

hahahahahaha, i reckon it's you mullins that does not have the clue. touch wood.


Postby ARRRRGHHHHHH!!! » Wed 29 Aug, 2012 00:09


Cloudy Blue Water... I was wondering if you ever managed to clear up your pool water, and if so... How? I added Floc and exactly the same thing happened to my water, I have tried adding Clear blue to little or no ovail. My chemical levels etc are balanced nicely but the water looks extremely cloudy. Please help if you can.



Postby texpeach25 » Fri 31 May, 2013 18:43

We have flocked our pool on several occasions and are about to do it again this evening bc we had a lot of rain a few weeks ago & we are just now getting it back under control. It DOES WORK!! Everyone we know does it & it works. We do NOT run the pool very long after we flock and it has to sit quite a while for it to clear up. It also does NOT seem effective to use our automated vac. We use a hand held bc the automated stirs up the water too much so it just stirs it up & it continues to look cloudy. We use a very long pole & long hose.
I can understand your frustration but flock DOES WORK!


Postby Clearwater » Mon 03 Jun, 2013 21:43

To clear murky water, try using Alum (Aluminum Sulfate) you can purchase this in most pool supply stores, they don't recommend this product because it doesn't cost much and they want to make a killing selling you products that may or may not work quickly enough.

Turn off your pool....sprinkle some of the Alum over the surface of the pool but don't over do it....wait 12 hours...vacum the pool slowly with the filter setting on waste! Replace the lost water, filter, and back wash every 4 hours for a min or two......The water usually clears up within the first 12 hours...if it is not clear...turn off pump...let all the debris settle to the bottom of the pool and repeat the vacum process...DO NOT ADD MORE ALUM (ALUMINUM SULFATE).
Frustrated in IL


Postby Frustrated in IL » Tue 25 Jun, 2013 22:54

Arghh!! This thread is so frustrating! Everyone seems to be an expert and no one agrees on anything. I've just read all 15 pages and am more confused than ever. Floc, don't floc, vacuum, don't vacuum, leave the filter running 24/7, shut the filter off. Stop the madness! Not trying to offend, just wanted to share my reaction after over an hour of reading this thread.

Fwiw, here's my situation...
I have a 13,000 gallon above ground pool with a cartridge filter. I use two chlorine puck filters. I've used this pool for three summers and had no problems the first two summers. However, this last winter was the first winter the pool was left up. Unfortunately, a lot of leaves fell into the pool upon opening and the water was a very green swamp. I removed all of the leaves and shocked and it quickly turned into a pretty shade of pale green and then... stopped. At this point, I decided to ask for help.

We have two pool stores in town. I chose one and quickly left when the lady told me (within the first 30 seconds of me being in her store) that she wasn't "very pool savvy." So, I left and went to Pool Store #2. Well, fast forward two weeks later and you can predict the outcome: two samples and $50 worth of chemicals later and my water is still not clear. There has been one minor change: the pretty pale green is now a pretty pale blue. I had been leaving the filter on 24/7 (and cleaning the cartridge regularly) but, after my reading marathon here, have decided to turn it off overnight. I'll keep my fingers crossed and check first thing in the morning. I'm also going to try to vacuum tomorrow but not sure I can figure out the "filter to waste" option everyone on here is talking about. I'm also considering using some type of floc but honestly don't want to spend more money unless I *know* it'll fix my problem.

Here are the results of my latest reading, June 18, 2013-
FC- 0
Total chlorine- .4
pH- 7.1
Tot. Alkalinity- 113
Tot. Hardness- 85
CYA- 0

I was concerned about the CYA and considered looking into acid but the pool store lady told me that wasn't a problem. She just wanted me to add some chlorine and Phos-Free, both of which she was happy to sell me. I did a check with a strip tonight and chlorine now seems to be okay, according to the strip. I know those strips aren't always the most reliable but it's all I had and I really don't want to go back to the pool store. I do plan on investing in a better pool test kit eventually.

Sigh... Anyone think they can help me? Thank you in advance *very* much!

chem geek
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Posts: 2381
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Postby chem geek » Wed 26 Jun, 2013 15:14

There are not multiple opinions from experts. Anyone can post in a thread and very, very, very few people actually know anything about pool water chemistry.

First of all, you can't trust pool store testing of your water. Yes, maybe your pool store is using an accurate test and maybe the person doing the test, usually a part-time summer-only student, was trained properly in how to do the testing, but more often than not the tests are either poor or the tester doesn't do the tests properly or the results are put into a program that promotes sales of chemical products. Remember that the pool store is in business to make money, not to help you in the least expensive way. If they can sell you algaecide, phosphate removers, clarifier, flocculant, enzyme, metal ion products, etc. then they have a very strong incentive to sell you these high margin products. If they can sell you Alkalinity Up which is nothing more than sodium bicarbonate which is identical to Arm & Hammer Baking Soda you can get for much less at a grocery store, then they will usually not tell you that tidbit of helpful information. Nor that pH Up product is nothing more than sodium carbonate which is identical to Arm & Hammer Super Washing Soda (careful: NOT the laundry detergent) or that you could use 20 Mule Team Borax to raise the pH instead and have less of a rise in TA. Nor do they tell you that you can use Peladow or Dowflake calcium chloride ice salts instead of Calcium Hardness increaser. See this post for details and links that prove what I just wrote. Yes, there are some very honest and helpful pool stores, but most manufacturers of these chemical products do not tell the pool store people the truth about them -- it's not all the pool store's fault, but that doesn't mean that you, the consumer, don't get deceived.

If the CYA level is truly zero, then if your pool is outdoors and exposed to sunlight, then it absolutely positively needs CYA in the water or else chlorine that you add will get cut in half every hour in direct noontime sun. Adding pure CYA is slow to dissolve and while the least expensive approach, if you are in a hurry and have to shock the pool with chlorine anyway, then using Dichlor is the fastest way to add both chlorine and Cyanuric Acid (CYA) at the same time. This is because of the following chemical facts that are independent of concentration of product and of pool size -- facts that hardly any pool store or chemical manufacturer will tell you:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it will also increase Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it will also increase CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it will also increase Calcium Hardness (CH) by at least 7 ppm.

You should get your own good test kit, either the TFTestkits TF-100 or the Taylor K-2006 with the former kit having more volume of reagents you use the most (both kits use Taylor reagents and chemistry).

Then, what you should do depends on your ACCURATE water chemistry parameters. This is because there are at least 100 Reasons for Cloudy Swimming Pool Water. The most common reason is algae growth and that is most likely when the FC level is too low relative to the CYA level so algae is then able to grow faster than chlorine can kill it. Another reason could be that your pool is too high in some combination of pH, TA and CH so that you have over-saturation of calcium carbonate (I think that less likely in your case given the history you gave). You could have added incompatible chemicals such as certain types of metal sequestrants that are anionic polymers with certain types of algaecides (e.g. Polyquat 60) that are cationic polymers (again, less likely given the history you gave). And so on. Starting with an accurate set of water chemistry parameters and some relevant history of the pool prior to the cloudiness will help a lot.

From what you wrote, you were using Trichlor pucks. As I noted above, that increases the CYA level. So if your CYA level is truly at 0 then that can come from a bacterial conversion of CYA into ammonia or nitrogen gas over the winter when the FC was left to go to 0. If the conversion resulted in ammonia, then the chlorine demand can be huge, but with an accurate test kit you would see that after adding chlorine and waiting 10 minutes or so that the FC was still low or 0 while the CC was higher. You could also test with an ammonia test kit from a fish/pet/aquarium store as further confirmation.

(too many URLs so splitting this into two posts...)
chem geek
Pool Industry Leader
Pool Industry Leader
Posts: 2381
Joined: Thu 21 Jun, 2007 21:27
Location: San Rafael, California


Postby chem geek » Wed 26 Jun, 2013 15:16

(...continuing from previous post due to too many URLs)

I suggest you read the Pool School to learn more about how to maintain your pool. Some relevant articles depend on the specific reason for your cloudiness. If you have algae as the primary cause, but the pool will at least hold some chlorine though may drop over hours, then read Defeating Algae and The Shock Process. If you truly have no CYA then use Dichlor for some of the shocking, but not more than 30 ppm FC worth and then use chlorinating liquid or bleach (unscented, plain, NOT outdoor or splash-less). If the FC won't hold for 10 minutes even after building up the CYA and if you measure ammonia in your test kit of have high CC, then see this post for what I did in terms of frequently adding a lot of chlorine before it held, though you could do a separate bucket test of pool water to see how much chlorine demand is really there knowing that 1/4 teaspoon of 6% bleach in 2 gallons is 10 ppm FC. You may decide that some water replacement will be less expensive than adding lots of chlorine.

But whatever you do, do not mix pool store advice with what you should do based on your own accurate test results.
Frustrated in IL


Postby Frustrated in IL » Wed 26 Jun, 2013 21:51

Whew... You've given me A LOT of information to take in and act upon. Thank-you so much! It sounds like the first step is to order a decent test kit. I'll do that and began reading the various article you mentioned in your post.

Thanks again! :)



Postby Guest » Sun 04 Aug, 2013 12:17

get PH to 7.2 and do NOT add any more chlorine. filter continous and backwash at least once per week

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