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Thread: Free and Combined Chlorine not changing

  1. Back To Top    #1

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    Free and Combined Chlorine not changing

    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!
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

  2. Back To Top    #2

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    Re: Free and Combined Chlorine not changing

    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?
    Lisa
    Intex AG vinyl 15' x 48" 4,300 gallons due to skimmer install, Krystal Clear SF pump combo 2800 GPH, Krystal Clear SWG, Pool Blaster Max vacuum, Hayward thru the wall skimmer, TF 100 test kit with speed stir, K 1766 Taylor salt test, My SLAM Process

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    Re: Free and Combined Chlorine not changing

    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
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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  4. Back To Top    #4
    Defgufman's Avatar
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    Re: Free and Combined Chlorine not changing

    We need cya numbers to give advice
    Inground 13,200 gal Vinyl, Pentair 3/4 hp pump, Pentair Sand Dollar filter, Polaris 280

    Pool School, Pool Math, CYA to FC ratio chart, Testing Kits

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    Divin Dave's Avatar
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    Re: Free and Combined Chlorine not changing

    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.
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

  6. Back To Top    #6

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    Re: Free and Combined Chlorine not changing

    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.
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

  7. Back To Top    #7

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    Re: Free and Combined Chlorine not changing

    Always get test water from elbow deep
    Lisa
    Intex AG vinyl 15' x 48" 4,300 gallons due to skimmer install, Krystal Clear SF pump combo 2800 GPH, Krystal Clear SWG, Pool Blaster Max vacuum, Hayward thru the wall skimmer, TF 100 test kit with speed stir, K 1766 Taylor salt test, My SLAM Process

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    Re: Free and Combined Chlorine not changing

    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.
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

  9. Back To Top    #9

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    Re: Free and Combined Chlorine not changing

    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.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    Re: Free and Combined Chlorine not changing

    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.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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  11. Back To Top    #11

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    Re: Free and Combined Chlorine not changing

    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.
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

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    Re: Free and Combined Chlorine not changing

    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.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  13. Back To Top    #13

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    Re: Free and Combined Chlorine not changing

    So if this Chlorine free shock doesn't do the trick... how do I get rid of the CC?
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

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    Re: Free and Combined Chlorine not changing

    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.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

  15. Back To Top    #15
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    Re: Free and Combined Chlorine not changing

    How are you getting CC test results as precise as .2?



    There is no need to use 25ml of water & so many 871 drops, use the test with 10ml of water & each drop counts as .5
    I consider myself very lucky I found this site before the pool store found me-pool owner since Nov 2008- Stunningly clear 17,000 gal fiberglass pool, thanks to this site, installed in 1982-24" 3.1sq. ft sta-rite sand filter, 1 hp - 2 speed wisperflo pump-WFDS-4

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    Re: Free and Combined Chlorine not changing

    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.
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

  17. Back To Top    #17
    Mod Squad JVTrain's Avatar
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    Re: Free and Combined Chlorine not changing

    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.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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  18. Back To Top    #18

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    Re: Free and Combined Chlorine not changing

    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.


    30,000 gal inground (20 ft. x 40 ft. w/ deep end), vinyl liner, Pentair Clear & Clear 420 cartridge filter, single speed 1.5 HP Pentair Whisperflow pump, heat pump, SunTouch controller

  19. Back To Top    #19

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    Re: Free and Combined Chlorine not changing

    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?
    18'x32' Oval Radiant - 15,000 gallons - Semi Inground (built into hill) - vinyl liner.
    Doughboy Powerline XP1 2Hp Dual Speed Pump
    Doughboy Silica II Sand Filter
    Installed 6/20/2014

  20. Back To Top    #20
    Mod Squad pooldv's Avatar
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    Re: Free and Combined Chlorine not changing

    Yes, it could.

    Here is the process to SLAM - Shock Level And Maintain your pool. If you have passed the three criteria then it could just be a pollen issue.
    TFP Moderator
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