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Thread: Excessive Chlorine Use

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    Excessive Chlorine Use

    Howdy,

    I have been using BBB method for years with great success. This year, pool was opened, cleaned and ready to go within a few days and all seemed good with the world. However, I soon noticed that instead of my usual 1 jug a day of bleach I was using two just to keep up. Now I did trim back several trees and remove a larger tree over the fall, and maybe the pool does get some more sun, but double the bleach usage (almost 7ppm/day)?

    Thinking I may have an algae bloom lurking and barely being held in abeyance, I shocked the pool until the overnight loss was about 1 ppm and no FC, but still it seems to eat up chlorine.

    My numbers when I started: TC: 4; FC:0; PH 7.5; TA: 130; CYA: 50

    Shocked to 21+

    Once it held overnight after a day or so i let it drop, but it still loses about 7ppm a day - even with partly cloudy day.

    Is this my new normal or am I missing something? Is 2 jugs a day really what I am going to have to do - that's a lot of recycling!

    Thanks for any input!

    Gerry
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Mod Squad tim5055's Avatar
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    Re: Excessive Chlorine Use

    I can't tell from your description if you are following the SLAM directions fully. Read through the following article and see if maybe you are skipping a step.

    Pool School - SLAM - Shock Level And Maintain
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Texas Splash's Avatar
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    Re: Excessive Chlorine Use

    Gerry, Tim asks a good question. Could you also confirm please what test kit you are using to get those numbers?
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: Excessive Chlorine Use

    Taylor K-2006 test kit and I performed the SLAM according to that link. Only thing was brushing the pool - I was only able to do it once over 3 days, but I also did backwash.

    - - - Updated - - -

    Oh, I omitted 24/7 filter use - only did about 13hrs a day.
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Texas Splash's Avatar
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    Re: Excessive Chlorine Use

    In that case, as Tim noted above, it's very important to follow the SLAM directions to the "T". Any misses could compromise your success or take much longer. The SLAM link is below, along with the Chlorine/CYA chart which you will need to SLAM as well. Refer to both of those and remember:
    - Keep your FC at or slightly above the SLAM FC level
    - Brush, vacuum, agitate that water as much as you can; keep pump going 24/7
    - Do all of this until you meet the 3 criteria for passing SLAM

    Good luck.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Richard320's Avatar
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    Re: Excessive Chlorine Use

    That's too much FC loss.

    Either CYA is not what you think it is, or something's still growing in the pool. Can you clarify "until the overnight loss was about 1 ppm"? Using the FAS-DPD test you should be able to say it was .5 or .8 or 1.0 or 1.5 or something that's a multiple of .2 or .5 depending on the sample size.

    I'd start looking for lurking algae behind lights and beneath ladder steps.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Excessive Chlorine Use

    As for CYA, I've been doing this for many years, and I think I' on with that number and the reagent is relatively fresh. As for the overnight ppm loss, it was hard to tell with certainty whether all the pink disappeared with 1,2 or 3 drops. I retested and it disappeared at 2 drops, 1ppm.

    I do see what may appear to be a haze of algae this morning when I removed the ladder. I am starting again. Question: can I brush the walls, etc. by leaving Polaris on for a couple of hours? Also, the water is crystal clear, does that make a difference?

    Thanks for all the help!!!!
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Texas Splash's Avatar
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    Re: Excessive Chlorine Use

    Since you believe the CYA reading to be accurate, then that means something is growing in the pool, and you mentioned an algae haze this morning. So now implement SLAM and remember the 3 SLAM criteria: Overnight loss of no more than 1ppm FC, CC < .5, and clear water. If you haven't passed all three, continue to SLAM and get it done completely or it will just return and you'll have to start all over. Best of luck.

    - - - Updated - - -

    Make sure you check the ladder and any other items that come in contact with the water.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Mod Squad tim5055's Avatar
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    Re: Excessive Chlorine Use

    The primary purpose of brushing is to get to the algae. Some algae can develop a biofilm over them as a protective layer that chlorine may not penetrate. The bristles of the brush break this up and expose any algae thus protected tot he chlorine.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Excessive Chlorine Use

    Ok. Started afresh on Saturday - shocked to 24 then swept and checked every few hours. Ended up adding about 5 jugs of bleach Saturday. Overnight loss about 2ppm. Repeated steps Sunday. This morning, loss of 1.5 ppm so swept and shocked again - this time to about 26. Pool is immaculate and no CC. How long does should this take - it is much harder to keep up with it on the work days. Finally, I take a level just before bed to confirm still at shock level - all has been good. However, what to do if it is not? Do I wait until the next day or add that night? If I add, how can I do the overnight FC loss test if I don't know the value right after I add? Just curious and thanks for the help!!!!!

    I have also built a contraption for getting a pool sample without getting wet up to my armpit on my hands and knees. Will post pix later today.
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Texas Splash's Avatar
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    Re: Excessive Chlorine Use

    Maintain the SLAM until 3 objectives are met:
    1. Water is clear
    2. You do not lose any more than 1ppm of FC overnight (that's the OCLT)
    3. CC (Combined Chlorine) is <.5
    ** You MUST meet ALL 3 items above to properly do a SLAM. anything else and there’s a good chance your algae will return. Sounds like you're about at the end, so don't give-up now. Keep that FC at the higher FC SLAM level". Be thorough, consistent, and finish it up right so you don't' have to do it again. You're doing great!

    - - - Updated - - -

    When you've meet all 3 items above, then you can start letting the FC come back down to its regular "Recommended Level"
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: Excessive Chlorine Use

    You must MAINTAIN the shock level. So, checking chlorine levels frequently is imperative.... as is adding chlorine if the levels drop. SLAM is a process and allowing the chlorine to drop below the prescribed level virtually restarts the process.

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    Saturn94's Avatar
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    Re: Excessive Chlorine Use

    Make sure during the SLAM process you are running the pump/filter 24/7. I've seen it happen where daytime losses while the system was running were high, but no overnight loss with system off. In that case something in the filter/system was eating up chlorine.

    If you have a light it's also a good idea to remove it, clean thoroughly behind it, and let it float in the pool during SLAM.
    20k IG vinyl liner/Aqua Rite SWCG, T-15 cell/Hayward Pro Grid 6020 DE filter/Polaris 280 with booster pump/Hayward Superpump 1 hp/city water/pool installed March 2004

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    Saturn94's Avatar
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    Re: Excessive Chlorine Use

    Quote Originally Posted by Undrwtr1 View Post
    Ok. Started afresh on Saturday - shocked to 24 then swept and checked every few hours. Ended up adding about 5 jugs of bleach Saturday. Overnight loss about 2ppm. Repeated steps Sunday. This morning, loss of 1.5 ppm so swept and shocked again - this time to about 26. Pool is immaculate and no CC. How long does should this take - it is much harder to keep up with it on the work days. Finally, I take a level just before bed to confirm still at shock level - all has been good. However, what to do if it is not? Do I wait until the next day or add that night? If I add, how can I do the overnight FC loss test if I don't know the value right after I add? Just curious and thanks for the help!!!!!

    I have also built a contraption for getting a pool sample without getting wet up to my armpit on my hands and knees. Will post pix later today.
    If FC is below SLAM target when you test in the evening, go ahead and add chlorine, test again in a half hour and use that number as your starting OCLT number.

    If work limits the number of times you can adjust FC each day, then go ahead and raise it over SLAM target each time you adjust to give yourself some wiggle room.
    20k IG vinyl liner/Aqua Rite SWCG, T-15 cell/Hayward Pro Grid 6020 DE filter/Polaris 280 with booster pump/Hayward Superpump 1 hp/city water/pool installed March 2004

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    Re: Excessive Chlorine Use

    Thanks folks - and BTW here is my new invention so I don't get messy testing and SLAMming in a suit and tie during lunch!!! Pull one string to keep bottle inverted, pull other string to turn bottle right-side up to fill at depth. Works like a charm.
    Attached Images Attached Images
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Re: Excessive Chlorine Use

    Quote Originally Posted by Undrwtr1 View Post
    As for the overnight ppm loss, it was hard to tell with certainty whether all the pink disappeared with 1,2 or 3 drops. I retested and it disappeared at 2 drops, 1ppm.
    I am concerned about your wording here. It sounds like you are describing the CC test (combined chlorine), and maybe assuming that the slam is done once you vhave 1ppm or less of CC.

    The OCLT is where you are at or above slam level at night, after the sun goes down, and you take your FC reading (Which should be at least 20 drops). then early in the morning you do the same test to see how much FC you've lost overnight.

    When you said it was 2 or three drops...that just can't be an OCLT test....
    10,500 gal IG, Topaz Pebble, auto-level
    Hayward DE filter, 2HP Ecostar VSP, ProLogic PS-4, GVA actuators
    Cal Pools Wave Force Plus (wall return jets plus 2 floor pop-ups), Venturi Skimmer
    Water sheer, 2 wok pots, bubbler stem on the baja step
    ColorLogic Mutlicolor LED lamp. Taylor 2006+speed stir

  17. Back To Top    #17

    Re: Excessive Chlorine Use

    Chris,

    I should have said "within" not with. Sometimes, when counting 30 - 50 drops of reagent quickly it is hard to tell exactly which drop caused the pink to disappear. I have since slowed down so my older brain can keep up. It is much easier with a few drops for a regular daily FC check. But when SLAMming, and with 40-50 drops of reagent (10ml sample) it gets mesmerizing watching the drops while trying to watch for the color change. Figuring the difference between whether the pink disappeared at drop 42 or drop 45 screws up the whole overnight 1ppm magic number evaluation!!

    Gerry
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

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    Join Date
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    Re: Excessive Chlorine Use

    ok good. that would probably have been too easy a solution.
    10,500 gal IG, Topaz Pebble, auto-level
    Hayward DE filter, 2HP Ecostar VSP, ProLogic PS-4, GVA actuators
    Cal Pools Wave Force Plus (wall return jets plus 2 floor pop-ups), Venturi Skimmer
    Water sheer, 2 wok pots, bubbler stem on the baja step
    ColorLogic Mutlicolor LED lamp. Taylor 2006+speed stir

  19. Back To Top    #19

    Re: Excessive Chlorine Use

    Ok. Started Saturday with every two hour checks, adding bleach as necessary, sweeping pool, pump on 24/7. This morning (Wednesday) was the first where overnight loss was zero. I will now let FC swing down to normal levels. When I check FC tomorrow morning, should that give me a general idea of what the daily FC loss will be or does it lose more when there is higher FC? Curious.

    Finally, while I appreciate all the help, I am very paranoid that the FC loss will still be very high and I'll have to start over. Should I be adding algaecide weekly? Thanks again!

    Gerry
    Pool: 25,000 gal.(appx.)/IG/Vinyl/DE
    1.5 HP superpump / Filter Flow Rate - 72gpm (as per spec.)
    Hayward 300,000 BTU natural gas heater / Polaris 380
    Long Island, NY

  20. Back To Top    #20

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    Re: Excessive Chlorine Use

    First of all, you invention is the cat's pajamas. I am too old for a suit and tie now but that is just really neat.

    Secondly, ALWAYS remember this principle......two things consume chlorine in your pool and ONLY two things. UV from the sun and organics in your pool water. That's it.

    With a CYA of 50 ppm, you have minimized your loss from the sun, leaving you with one inescapable conclusion....organics were/are in your pool.

    Algaecides are not the answer. More chlorine is the answer.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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