Trouble clearing up cloudy water.

vtdhc

Member
Aug 1, 2014
24
Saint Albans, Vermont
I'm helping my son try to clear up his pool water. He has a 27' above ground and the water is too cloudy to see the pool bottom. We have had it up to shock level FC or above for about a week but little or no improvement in the cloudy water. We use a TF-100 test kit and the CYA is at 40 so we were keeping the FC level at 16 - 22 ppm. When we started the ph was at 7.8 but today it is at 6.7 so tomorrow we will add borax to get the ph back up. Also the TA is at 50 so we will also add baking soda to raise that to about 100. Last night my son did the OCLT and the pool used no overnight FC. We're not sure why we have not been able to clear the cloudy water. Looking for some suggestions.....
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,260
Tucson, AZ
How are you adding chlorine? The recommended liquid chlorine would not make the pH drop like that.
TA of 100ppm is higher than you would want if you are using bleach.

What kind of filter does he have?
 

vtdhc

Member
Aug 1, 2014
24
Saint Albans, Vermont
Originally the CYA was at zero so we added 2 gallons of liquid stabilizer to get the CYA to 40 ppm. While waiting to receive the Liquid stabilizer we used tricor chlorine pucks to get some CYA in the pool. After the CYA was at 40 ppm we switched to 10% liquid chlorine. I know the pucks will lower the PH but it was at 7.8 when we switched to 10% liquid chlorine. I guess we will adjust the TA to between 70 - 90 ppm as recommended. He is using a used but new to him sand filter. It was claimed the sand was replaced last year.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,666
Evans, Georgia
Whoa.... one gallon of liquid stabilizer in my pool raises my CYA 32ppm, so unless his pool is a lot bigger than my 11500 gallon pool he's gone too high on that.

Need more information, please. Size of his pool, filter info and what is being used to chlorinate?

Maddie :flower:
 

vtdhc

Member
Aug 1, 2014
24
Saint Albans, Vermont
27' diameter, 46" water depth estimated at 18,500 gallons. The CYA is 40ppm, using a standard sandfilter and liquid chlorine as already posted. Headed to the store to get borax, baking soda and make adjustments. Will post new reading when complete.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,260
Tucson, AZ
Nothing you have added should have lowered the pH like that.

I would retest. Also don't raise the TA higher than 70ppm, I would be inclined to leave it for now and focus on clearing up the water.
 

vtdhc

Member
Aug 1, 2014
24
Saint Albans, Vermont
I added 1.5 boxes of Borax to get the PH up to 7.5 and the TA measured 70ppm (didn't add any baking soda). The FC was at 8.5 ppm and the CYA 40ppm. There may be a very slight improvement in the water clarity. I think I can just barely see the bottom of the pool's vinyl pattern. Does anyone have a suggestion? So far there has been none.
 

Lemonred34

Well-known member
May 5, 2019
155
Louisiana
You are SLAMing pool? Was it green when you started or just cloudy? How often does he run the filter?

Assuming there are no filtration issues, sand filters in general take the longest to clear a pool. You can try adding DE to the sand filter to help things move a little quicker.
 

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
11,666
Evans, Georgia
You need to be focused on liquid chlorine and filtering only at this point. The SLAM process will work but it takes effort to test as often as possible (and at least 3x a day at minimum, but more is better) and re-dosing to bring the FC up to the correct level to perform the SLAM.

Soooo.....for a CYA of 40, that pool should be maintained at a FC level of 16ppm around the clock, with constant pump and filtration running.

Adding a bit of DE can help when you're rounding the bend at the end of a SLAM. Backwash the filter when the pressure raises 25% offd clean pressure reading.

Stop adding anything else to that pool at this time other than liquid chlorine. Use PoolMath (look for web version at the bottom of this page) to guide quantities.

Maddie :flower:
 

vtdhc

Member
Aug 1, 2014
24
Saint Albans, Vermont
For a little more background, at the start of the pool season the pool was green and filthy. The pool was uncovered last winter and had lots of leaves etc. in the water. My son first got in with waders, scooped, vacuumed, backwashed etc. multiple times then added lots of liquid chlorine. This process cleaned things up considerably. Eventually the water was clean but very cloudy and adding the chlorine did not improve things. That is when my son asked me for help. I thought we would start with the SLAM process and that is when we found the CYA was at zero. We added Trichlor pucks for a start to get some CYA in the pool because the liquid stabilizer would take almost a week to arrive. We then added two gallons of stabilizer which got the CYA to 40ppm and switched to only liquid chlorine. We then kept the FC chlorine level at between 16- 22 ppm for over a week and running the pump & filter 24/7. Using the OCLT method we determined the FC was dropping overnight so we still had junk in the pool. A few days ago we passed the OCLT test when the FC was unchanged overnight. We have allowed the FC to come down to a normal level for CYA of 40 ppm. We expected the water to clear but it has not (or maybe is starting to clear but is very minor if at all). It is difficult to tell. I'm starting to think this is just going to take a long time to clear the cloudy water. Does anyone think raising the FC to shock level will help or is it just going to take time with the FC at a normal level. Using DE may be a good choice as was suggested. Thanks.

Dave.
 

Teald024

TFP Guide
Yes, you should still be at shock levels of FC. You never passed one of the most important criteria: clear water. You should still be in full SLAM mode. Get that FC up until the water is crystal clear.

Unfortunately AGPs are notoriously difficult to get good circulation. The return is right near the skimmer.
 
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