Free and Combined Chlorine not changing

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Can anyone help solve this enigma?

Five days ago my chlorine results were
FC 3
CC 1.5

I was instructed by the pool store to shock... so I did.

Yesterday my results were
FC 6.2
CC 1.4

I decided to use the TFP method and my new Taylor test kit to handle it myself.

I did that math to bring my FC up to 14 (10x the CC) using bleach. I did this last night at 8 p.m.

At 11:00 this morning I did another test.

FC is at 14 (it didn't decrease over night?)
CC is at 1.4

Why are my FC and CC staying the same?

I think I remember this starting to happen at the end of the season last year. The pool store told me I had phosphates which were preventing the Chlorine from doing its job. Does this sound right?

I'm going out to purchase a phosphate test kit shortly.

Does anyone have any advice or know what could be going on?

The pool gets full sun pretty much all day. It's an sem-inground vinyl liner sand filter. The rest of the results were all in the normal range.

Thanks so much!
 

Azgirl71

Platinum Supporter
TFP Guide
Apr 9, 2015
2,586
Sierra Vista, Az
Don't worry about phosphates.

it will take time for your CC to drop. It is good that you did not lose FC over night.

if you are SLAMming keep your FC level up.

what is your CYA?
 

Donldson

TFP Expert
LifeTime Supporter
Jun 12, 2009
4,588
NW Ohio
Did you measure your FC at 14 last night, or are you just assuming it was 14 because that is how much chlorine you added?

I second AZgirl, phosphate levels are irrelevant.

From my HTC One via Tapatalk
 

Divin Dave

TFP Expert
LifeTime Supporter
Oct 2, 2013
5,681
Longview, Texas
1st piece of advice.
Forget the pool store. Their methodology and TFP are diametrically opposed to each other.

Next.
Post up your CYA test result just so we are all on the same page.

Next
Continue to SLAM until 3 criteria are met.
1. CC is less than .5 (1 drop to clear)
2. OCLT shows less than 1 ppm FC loss
3. Water is crystal clear

Its that simple.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thank you for all your responses.

I went to Leslie's because it was the only place open today.

My phosphates are through the roof. She said you don't really worry about them unless they get as high as mine are (1100) and only then because if I ever do develop algae, the phosphates are food for it.

CYA was a 70 today.

She also got 14 as a free Chlorine reading, but she got a zero for combined chlorine. She was using a Taylor kit. I am so confused as to how that is possible.
I'm about to go out and do another test myself. The only thing I can think of is... when I did the test myself, the water came from near the surface... and I have a TON of a pollen floating around the surface right now. When I took the sample to Leslie's, I took a sample from arm's reach below the surface. I'll come back and post my results after I test.


The water is crystal clear.. it has been since we took the cover off.

Thank you all.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Ok here are my latest results...

FC - 11.5
CC - 1.2 or 1.3 (second drop just about cleared it)
pH- 7.4
TA- 110
CH- 300
CYA- 35-40 ... I don't like this test. I feel like I can always see the black dot. First test I'd say was a 40.. second test was more a 35. Leslie's said 70.
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,516
Tucson
CYA test is the most difficult to read. You should hold the tube in front of you about waist high, standing with your back to the sun. Your result is when you cannot see the dot at all. Lighting can affect your reading, but you can always pour the sample back into the mixing tube, then into the reading tube over, and over with the same mixed sample to see if your reading is consistent. Ask some one else to look at it in the same manner to confirm your results. Pretty soon you kind of get the hang of it, but it's always just a little bit subjective.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,430
Sebring, Florida
An important tenant of TFPC is trusting your own testing. You will drive yourself crazy comparing your results to pool stores. If pool stores were remotely accurate, there would be no point in owning your own kit.

In fact it is virtually essential to own your own precise kit because the pool stores testing has proven to be wildly inaccurate time after time.

If you got a valid cc's result, it is impossible for Leslie's to get a zero result.

Your CYA is 40....trust yourself 35-40 on two tests is very repeatable.

Now your original question was why no FC loss overnight......simply, there is a testing error on the AM test, or your pool is not the gallonage you think it is. Be sure you get to the endpoint of EVERY color change test. That endpoint is when you add the last drop and there is ABSOLUTELY no more color change. Subtract that last drop from your total and the result is your endpoint.

Never take your samples from the surface.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thank you all for your responses.

Any ideas then why my combined chlorine has only dropped .2ppm after raising to shock level twice?

Leslie's sold me a "Chlorine Free" shock to get rid of combined chlorine (which I was confused about if they got a reading of 0 ppm CC). I'm skeptical, but I read really good reviews online. I've already put it in. Going to do another FC/CC test this evening.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
34,430
Sebring, Florida
Any ideas then why my combined chlorine has only dropped .2ppm after raising to shock level twice?
CC's will go up and down when you change chlorine levels......perfectly normal.

Your "chlorine free" shock was expensive and unnecessary but done is done.
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,516
Tucson
Keep your FC above the shock level at all times and over time the CC will begin to drop. Any time FC drops below shock level, you are losing the battle. It has to stay above at all times.

CC is just FC that has been used to kill something organic in the pool, so once everything has been killed, the sun will begin to burn off the CC, and that number will begin to come down. As long as the CC stays up, there is something still going on in the pool. That's why we look for the CC to drop as one sign that SLAM is nearing its end.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Can someone please walk me through what to do?

This morning my FC is at 12 and my CC is back up to 1.5.

I've "shocked" twice, used the "non-chlorinating shock" twice, and dumped in a bottle of PhosFree to try to lower my phosphates a bit. The test I did yesterday was 2500+ ppb phosphates.

My chlorine results are from this morning.

My combined chlorine is not coming down. My free chlorine is bouncing around all over the place. It went from 9.5ppm yesterday evening to 12ppm this morning - the only thing I did different was the "non-chlorinating shock" (which I'm think is BS since how would my FC rise on its own?)

Do I just keep shocking and shocking and shocking? Please help. I'm super frustrated.
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
You need to rethink your ideas about how to clear your pool. Simply shocking your pool will not clear it and get rid of your CCs. You need to Shock Level And Maintain. SLAM. Read through the Pool School article. The MAINTAIN is the important part. You need to maintain at shock level until your water is crystal clear, your CCs are 0.5 or less and you pass the overnight chlorine loss test. Link to SLAM method is in my signature.
 

scott39

LifeTime Supporter
May 8, 2015
39
South Park, PA
I went down the phosfree path last year and it didn't help anything except the pool store's profits.

As others have advised, keep FC above shock level for your CYA until CC is less than 0.5, over night chlorine loss is less than 1.0 and water is crystal clear.


Sent from my iPhone using Tapatalk
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thanks. I'm new to all this ... this is my first time opening the pool for the year. Last year I let the pool store tell me what to do. This year I've realized they don't know what they're talking about any more than I do, and that I'm basically on my own, and that terrifies me because I don't know what I'm doing either.

Despite the CC results... my water is sparkling, crystal clear. There is not a SPECK of debris or dirt or otherwise on the bottom (I've vacuumed 8 times in the past week). The walls and bottom don't feel slimy.

- - - Updated - - -

I do, however, have a continuously forming solid layer of pollen on the surface. Could this be causing the CC results?