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Thread: CL 0

  1. Back To Top    #1

    CL 0

    Here is my pool story. Had a pool installed 3yrs ago. All was well until mid last year. I was mostly using the cheap little test strips that only test the 3 basics. Started to get some staining. Went to the local pool supply store, they gave me some stuff to clear up the stains, and also some some stuff to 'fix' my phosphate problem. After that my CYA went to about zero. I got that up, but the Cl is 0. Here are the numbers.
    CL 0, PH 7.4, TA 130, CH 250, CYA 80, Salt 3400 ppm.

    The PH is a bit low, could that be why I can't maintain the CL, or is something else wrong? I did clean the cell.
    The water is a a little cloudy and there is dirt like accumulation at the bottom, I am guessing it is some sort of algae, but I do not have any green algae. The water temp is at 55 now, but it will be going up soon as we get into the 80's later this week.
    I wish I found this site before I went to the local shop.
    Thanks in advance,
    Pat (from NC)
    20K IG fiberglass, Cartridge filter 200sqft 150gpm, 1.5 hp pump, SWG Pool Pilot Cell SC-36. Automatic pool cover.

  2. Back To Top    #2

    In the Industry
    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: CL 0

    Hi, Pat,

    Welcome to the forum!

    It seems like you need to shock your pool. You can find an article on how to do so in pool school. Keep in mind t5hat shocking a pool is a process that may take a few days.....not a one-time application.

    Read the article and post back any questions you have. Shocking and vacuuming to get the stuff off the bottom will probably get your pool sparkling.

    You Cl is 0 most likely because you have organics that are in your pool and consuming it. The other thought is your SWG is not generating Cl but I assume you have checked that.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3

    Join Date
    Mar 2007
    Coastalish 'down easter'

    Re: CL 0

    Pat, welcome to TFP!!

    Sounds like the SWCG might not be generating (it may think the water is too cold).

    Try adding a gal of 6% bleach to the pool in the evening, (this will bring your 20,000 gal pool to 3 ppm.) and see how much remains in the A.M. Overnight chlorine loss will indicate the presence of organics that need to be shocked out of the pool, as per Dave's advice
    Luv& Luk

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    SouthWest Alabama

    Re: CL 0

    Welcome Pat,
    I noticed that your water temp is 55º so the SWCG most likely isn't generating. Follow Dave & Ted's advice for getting chlorine in your pool. It's especially important given that you're temps are rising.

    If you haven't already you should start reading Pool School
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  5. Back To Top    #5

    Re: CL 0

    Thanks for the responses. I read the shock article and will pick up some bleach today.
    Appreciate your help,
    20K IG fiberglass, Cartridge filter 200sqft 150gpm, 1.5 hp pump, SWG Pool Pilot Cell SC-36. Automatic pool cover.

  6. Back To Top    #6
    Casey's Avatar
    Join Date
    Apr 2007
    SW PA

    Re: CL 0


    Please keep us updated!
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

  7. Back To Top    #7
    dmanb2b's Avatar
    Join Date
    Apr 2009

    Re: CL 0

    Welcome Pat. Great advice so far...the only thing I could add is that with a TA of 130 and the fact you plan on using a SWG...your PH of 7.4 is not low at all. 7.4-7.6 is just about perfect.

    As Bama mentioned, read pool school in it's entirety a couple time over and you will be trouble free and feel free to post us any Q when you do run into trouble
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

  8. Back To Top    #8

    Re: CL 0

    Here's my status. I did lose the CL overnight, so I went ahead and did the shock treatment. I added 10 gallons 6% to bring the level to 30 according to the CL/CYA chart. The pool is looking alot better. My question is that the instruction said to keep it at the shock level up until I am not losing CL. But my tester, PDP test kit only reads to 5 ppm. So I do I measure it above 5? Can I just add less drops and multiple the results?
    Thanks again y'all.
    20K IG fiberglass, Cartridge filter 200sqft 150gpm, 1.5 hp pump, SWG Pool Pilot Cell SC-36. Automatic pool cover.

  9. Back To Top    #9
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    SWSuburban Chicago, IL

    Re: CL 0

    In order to confirm the overnight loss while at shock level, you need an FAS-DPD test that test up to 50ppm. You really should consider supplementing your kit with the test, by purchasing it separately.

    You can try the dilution method, using distilled water. It will lose some accuracy however. Use 3 parts distilled water and one part pool water and multiply the results by 4. This will test FC up to 20 but it's not as precise as using an FAS-DPD test.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner

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