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Thread: Question about Chlorine Consumption

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    Question about Chlorine Consumption

    So this morning I tested my pool using a K-2005. My FAS-DPD kit has been ordered and was shipped today. My numbers were
    FC: 1
    CC: 0
    TC: 0
    PH: 7.6
    TA: 130
    CH: 450
    CYA: 100

    Used the Pool Math calculator and added nearly 2 (121oz) bottles of good ole 8.25% Clorox at 2:30pm. Pump has been running all day. Retested at 7pm and there was no change in my test. Is this normal?
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    I'm a newbie myself, but I figured I'd give this a shot - When I put your numbers into poolmath, using the CYA/Chlorine chart, it suggests that your FC target should be 12, and that you need 2.4 of the 121oz 8.25%

    As to the normal - I would think that you should see something, except/unless you have organic matter in the pool, or the sun is burning it off?

    - - - Updated - - -

    Also, you're probably going to get recommendations to replace some water to both bring down the CYA and the CH, which are both over target.
    27,000 gal. plaster IG with round spa built in 2007. TFT-100 test kit XL w/ Speedstir
    Jandy CL580 cartridge filter. Jandy 1.0 hp filter pump, 1.5 hp booster/spa? pump.
    Aqualink RS One Touch controls. Paramount PC2000 In-floor cleaning system (1.0 hp pump?). Jandy LX pool heater, apparently broken.
    Missing so much gear due to previous foreclosure, it's sad.

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    Mod Squad tim5055's Avatar
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    Re: Question about Chlorine Consumption

    When you say "there was no change in my test" does that mean at 7PM you were back down to 1ppm FC?

    Now, the bigger problem. 100 is the limit of the CYA test, so at this level we are unsure if it is 100 or some number above 100. Don't equate “just a little over 100” to a number, the tube is not marked for such extrapolation. At this point I would recommend at least a 33% water exchange to get the CYA down. For vinyl lined pools leave at least one foot of water in the shallow end to keep from floating the liner and all pool owners are cautioned that in areas with a high water table lowering the water too much can “float” the pool out of the ground.
    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: Question about Chlorine Consumption

    When your CYA reads as 100, it could in fact be greater than 100.
    100 is where the test tops out at.

    Like PrairieGirl said added, I believe you will be advised to remove water so that you get an accurate read on your actual CYA.
    AGP: 27' x 52" : 17,500 gallon
    300 lb. Sand Filter (75 gpm) / 1.5 hp pump
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    Re: Question about Chlorine Consumption

    I will probably need to drain and refill some. I have been at this TFP method for less than 24 hours so it's been a crash course that started with digesting the Pool School section and taking notes.

    Sadly Tim I did not check the FC/TC levels after adding Bleach so I am not sure if the level rose initially, but to answer your question, yes it was at 1 ppm around noon, I added the Bleach, retested at 7 pmish and I still got 1ppm.

    I'm looking forward to using the FAS-DPD test to see if I'm making a mistake testing even though the directions on the DPD test are straight forward.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    Everyone starts this method at the same place, so no shame in that at all.
    Nothing makes sense and then as you tinker around a bit at some point it all becomes clear, and coincidentally so does your water ~ I guess that's the beauty of this method


    I do believe you will have to replace some water, just because 100 is tops and you'll be instructed to be within a certain zone, that is lower.

    You are going to be thrilled you went this route, so stick with it
    AGP: 27' x 52" : 17,500 gallon
    300 lb. Sand Filter (75 gpm) / 1.5 hp pump
    Full Sun ~ All Day

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    Re: Question about Chlorine Consumption

    So update, I was reading the Taylor Testing & Treatment Guide with my K-2005 and I read that what I might be experiencing is bleach out on the Chlorine Test. Since the post man hasn't delivered my FAS-DPD Test kit, I'll have to wait to see if that truly is the case.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    I don't think it's bleach lockout, knowing the little bit I know I would imagine your CYA is higher than what the test is accurately able to detect (in excess of 100) so the amount of Liquid Chlorine/ Bleach you are adding, at the strength you are adding is not nearly "powerful" enough to enact change.

    Drain a bit of that water off, that will be time well spent. Your CYA is likely at an unmanageable level. When the CYA is elevated more Liquid Chlorine is required to reach Target for SLAM if you are running it at a modest concentration.

    Also save your CYA reagent. No need to test again until you have swapped a considerable amount of water out, you don't have to do it all at once, you can do it in intervals, but save the reagent because a bunch will need to come out before a difference is able to be detected by the test.
    AGP: 27' x 52" : 17,500 gallon
    300 lb. Sand Filter (75 gpm) / 1.5 hp pump
    Full Sun ~ All Day

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    Mod Squad tim5055's Avatar
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    Re: Question about Chlorine Consumption

    Quote Originally Posted by Tonka Tuff View Post
    I will probably need to drain and refill some. I have been at this TFP method for less than 24 hours so it's been a crash course that started with digesting the Pool School section and taking notes.

    Sadly Tim I did not check the FC/TC levels after adding Bleach so I am not sure if the level rose initially, but to answer your question, yes it was at 1 ppm around noon, I added the Bleach, retested at 7 pmish and I still got 1ppm.

    I'm looking forward to using the FAS-DPD test to see if I'm making a mistake testing even though the directions on the DPD test are straight forward.
    Quote Originally Posted by Tonka Tuff View Post
    So update, I was reading the Taylor Testing & Treatment Guide with my K-2005 and I read that what I might be experiencing is bleach out on the Chlorine Test. Since the post man hasn't delivered my FAS-DPD Test kit, I'll have to wait to see if that truly is the case.
    Generally most everyone who shows up here is taking a "crash course". I will admit, I was lucky that my pool was very clear when I got it - just CYA in the 250 range.

    It is possible the reagents are bleaching out at high FC levels. As you already concluded, the FAS-DPD test will prove what is going on.

    How does your water look? What issues are you having?
    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: Question about Chlorine Consumption

    The water is clear with the exception of dog hair. If you've seen any of my other posts, I was pool stored before finding the TFP website and added Phosphate Remover leading to a cloudy pool and climbing PSI. The water is back to regular clarity now and the PSI takes much longer to climb.

    The reasoning for thinking that it "could" be bleach out on my K-2005 test is because the TA test results a few times were Blue/Yellow. The testing guide said this can happen instead of getting Green/Red if the chlorine or bromine levels are high. Also, yesterday I did a water test for fun at the pool store and they said my Chlorine results were high. I know they're not to be trusted, but I can't help but think that they might have gotten lucky and gotten close given the results of my personal TA test.

    Regardless, I am planning on dumping about 20-25% of the water to start with to see what the CYA levels show first and foremost before tackling any other issues.

    Again I'm just guessing here without the FAS-DPD test.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    When you had your water tested yesterday, what number did they give that was "high"? What was the actual number?

    With regards to DKT113's comments, I had CYA near 300 when I first bought my house, and I never had a problem with bleach not affecting the FC - high CYA will not mask FC - the FC will show up just fine in my experience. Poolmath worked just fine to induce fluctuations in my FC readings by adding bleach. CYA's buffering effect isn't really noticeable in the OT or FAS/DPD tests, it's only noticeable when things start growing in your pool.
    8,500gal plaster in-ground with attached spa, two floor drains, one skimmer. Chlorine, City Water.
    Pentair WhisperFlo 1hp Pump, MagnaTek Midcentury EPlus motor, Pentair CleanNClear 200SF Cartridge filter, Purex Triton MiniMax 250 Gas Heater, Pentair SunLite, AutoFill.
    Kreepy Krauly Cruiser, TF-100 with SpeedStir. :D

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    Re: Question about Chlorine Consumption

    They have me a level of 5, but again the new guy was testing so it could've been higher. The service manager tried to step in and retest, but most of the water had been used. He did confirm though (as if that has any standing) that it was indeed high FC.

    Like I said, I'm only guessing here. However, their test said high chlorine, my test didn't change after adding nearly 2 gallons of bleach, and my TA test occaissionaly was Blueish/Yellowish indicating a false reading.

    Anywho. It's not like any of this matters at the moment. I won't be able to tell where the FC is until the kit arrives and I sure ain't trusting "Buy This" pool testing methods. I don't have anything growing that I can see, ha ha, so I'll just wait patiently.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    That's fine! I asked what they said only because it's a small bit of information (misinformation perhaps) that may help. 5 isn't really "high" depending on CYA, but your TA color results are interesting to me - I'd suspect maybe you're a lot higher FC-wise than you think you are.
    8,500gal plaster in-ground with attached spa, two floor drains, one skimmer. Chlorine, City Water.
    Pentair WhisperFlo 1hp Pump, MagnaTek Midcentury EPlus motor, Pentair CleanNClear 200SF Cartridge filter, Purex Triton MiniMax 250 Gas Heater, Pentair SunLite, AutoFill.
    Kreepy Krauly Cruiser, TF-100 with SpeedStir. :D

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    Re: Question about Chlorine Consumption

    I agree, I am thinking that's what I'll find. Thanks for the input. It's good to bounce thoughts off someone else. Thanks again.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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    Re: Question about Chlorine Consumption

    To give you a clue, I was running around a 20-22 FC when I first took over my pool to keep it sanitary - the TA test performed just fine color-wise. That's not to say yours is higher or lower than that, just another thing I noticed.
    8,500gal plaster in-ground with attached spa, two floor drains, one skimmer. Chlorine, City Water.
    Pentair WhisperFlo 1hp Pump, MagnaTek Midcentury EPlus motor, Pentair CleanNClear 200SF Cartridge filter, Purex Triton MiniMax 250 Gas Heater, Pentair SunLite, AutoFill.
    Kreepy Krauly Cruiser, TF-100 with SpeedStir. :D

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    Re: Question about Chlorine Consumption

    So I thought I'd update my numbers today since I got the FAS-DPD test in this thread since I was suspecting that my chlorine levels were higher than my K-2006 test could handle. Here's what I got:

    FC: 45
    CC: ~4
    TC: 50
    PH: 7.6
    TA: 100
    CH: 500
    CYA: >100

    So I have 2 questions. First, I am assuming the best course of action at the moment is to do a partial drain and refill to drop the CYA levels so the chlorine levels fall back to normal.

    Secondly, Could my SWCG be producing too much chlorine? The setting has been on 80% since it was installed. I did bump the level up to 100% for a few days, but it's back to the levels set initially. I know that my CYA is preventing some of my FC from burning off as it would normally, but I wasn't sure if the SWCG was adding to the problem.
    FL Resident
    IG 18,000 gal plaster
    Hayward Swim Clear Cartridge Filter
    Hayward Swimpure Extreme swcg
    A.O. 1HP motor

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