Cloudy immediately after adding chlorine

RASSRQ

LifeTime Supporter
May 25, 2010
4
Sarasota, FL
I have a pool service that treats our pool every Wednesday. For some time now, the water is crystal clear until he adds chlorine (muriatic) on Wednesday AM. Then, almost immediately, the water becomes very cloudy. By about 24-36 hours after that, it's completely cleared again and will remain so until his next service.

Below is a sample analysis done by Pinch-A-Penny taken the day before the recent pool service:

Total chlorine: 3.0 ppm
Free chlorine: 3.0 ppm
Combined chlorine: 0.0 ppm
ph: 7.6
Total alkalinity: 100 ppm
Calcium hardness: 250 ppm
Stabilizer: 50 ppm
Total dissolved solids: 3,000 ppm
Sequestrant: 4
Adj. Alkalinity: 83

-- Is the cloudiness normal?
-- What is the chemistry that's causing the cloudiness?
-- Is it any cause for concern (aside from aesthetics)? And if so, what should be done about it?

Thank you ....
 

zea3

Mod Squad
TFP Expert
LifeTime Supporter
Jul 10, 2009
11,720
Houston, Texas
RASSRQ said:
I have a pool service that treats our pool every Wednesday. For some time now, the water is crystal clear until he adds chlorine (muriatic) on Wednesday AM. Then, almost immediately, the water becomes very cloudy. By about 24-36 hours after that, it's completely cleared again and will remain so until his next service.

Below is a sample analysis done by Pinch-A-Penny taken the day before the recent pool service:

Total chlorine: 3.0 ppm
Free chlorine: 3.0 ppm
Combined chlorine: 0.0 ppm
ph: 7.6
Total alkalinity: 100 ppm
Calcium hardness: 250 ppm
Stabilizer: 50 ppm
Total dissolved solids: 3,000 ppm
Sequestrant: 4
Adj. Alkalinity: 83

-- Is the cloudiness normal?
-- What is the chemistry that's causing the cloudiness?
-- Is it any cause for concern (aside from aesthetics)? And if so, what should be done about it?

Thank you ....
In your post you said "...until he adds chlorine (muriatic)..." Is he also adding muriatic acid? There is no muriatic chlorine. What metal do you add sequestrant for?
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
I will venture a guess that if FC is at 3.0 the day before he comes, then you are on the verge of a visible algae bloom. At CYA 0f 50 that FC of 3.0 is a bit below the recommended minimum of 4.0, so the water ought to be starting to look a bit dull. You may find some algae if you look for it, in the nooks and crannies around ladders and such. So, when he shocks the pool that algae turns white and clouds the water until the filter gets rid of that.

The other possibility is that this is calcium clouding from using cal-hypo to shock the pool but I rather doubt that as the CH does not seem high enough for that. Wiser ones may be able to weigh in on that thought.

If it is algae that is causing this, you can prevent that by adding some chlorine on your own when levels get to 4.0. I don't know what volume your pool is, take a look at the Pool Calculator to find that as well as the amount of 6% bleach that it would take to add 1.0 or 2.0 ppm chlorine to your pool.