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Thread: Tf-100 chlorine drop test inconclusive

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    Tf-100 chlorine drop test inconclusive

    I just tested my water for chlorine levels using the drop test. I tested for FC by adding one heaping scoop of R-0870 powder. The water turned pink as expected. Next I added 5 drops of R-0871 and the water turn clear again.. When I try testing for CC by adding 5 drops of R-0003, the water remains clear, which per the directions of the TF-100 kit it means I have no chlorine. How is this possible? I am confused. Please advice.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Richard320's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    You have no Combined Chlorine, which is ideal. Your FC is either 1 or 2.5, depending on the sample size you used, and is too low if you have any CYA in the water.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: Tf-100 chlorine drop test inconclusive

    The FC shows you have low chlorine.
    CC of 0 is good.
    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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    Divin Dave's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    R0870 + 5 drops of 0871 = 2.5ppm Free Chlorine
    using 10ml sample, miltiply number of drops to go clear x .5 (or divide by 2)

    If when adding 5 drops of R0003, the solution does not turn pink, then you have 0ppm of Combined Chlorines (which is a good thing).
    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.
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    Re: Tf-100 chlorine drop test inconclusive

    Thanks




    Quote Originally Posted by Richard320 View Post
    You have no Combined Chlorine, which is ideal. Your FC is either 1 or 2.5, depending on the sample size you used, and is too low if you have any CYA in the water.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Tf-100 chlorine drop test inconclusive

    My CYA is 60 PPM. Is this a bad thing or should I be concern?
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Tf-100 chlorine drop test inconclusive

    No you have a SWG so that is not bad. Ideally 70-80 is what is recommended.
    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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    Mod Squad jblizzle's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    See the FC/CYA Chart ... you likely want to raise the CYA a bit and raise the FC a bit.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Tf-100 chlorine drop test inconclusive

    Really! I though to much CYA does not let the Chlorine sanitize properly.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Divin Dave's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    If your FC is not in the correct proportion to the CYA level, then it will be buffered too much and be ineffective.
    The higher the CYA, the higher you need to bump up the FC to overcome the buffering effect.

    The correct target FC level is 11.5% of the CYA level and the minimum FC is 7.5% of the CYA level.

    Quote Originally Posted by RESISTENCIA13 View Post
    Really! I though to much CYA does not let the Chlorine sanitize properly.
    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 !!

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    Mod Squad jblizzle's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    Your SWG will not have to work as hard at the higher CYA levels because even though the FC level is higher, you lose fewer ppm to the sun each day.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Tf-100 chlorine drop test inconclusive

    11.5% of 53 (my CYA level) is 5.83. Is it 5.83 a bit high for FC?



    Quote Originally Posted by Divin Dave View Post
    If your FC is not in the correct proportion to the CYA level, then it will be buffered too much and be ineffective.
    The higher the CYA, the higher you need to bump up the FC to overcome the buffering effect.

    The correct target FC level is 11.5% of the CYA level and the minimum FC is 7.5% of the CYA level.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Mod Squad jblizzle's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    As I said before:
    Quote Originally Posted by jblizzle View Post
    See the FC/CYA Chart ... you likely want to raise the CYA a bit and raise the FC a bit.
    I think you need to do more reading as it appears you are still falling for the incorrect pool store rhetoric.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Tf-100 chlorine drop test inconclusive

    Quote Originally Posted by RESISTENCIA13 View Post
    11.5% of 53 (my CYA level) is 5.83. Is it 5.83 a bit high for FC?
    Nope. When I started with my pool, I inherited a CYA of roughly 240. We were swimming in 20 FC with no problem. I had to keep it up there to avoid algae. I don't recommend it to anyone, but it does demonstrate that it's the ratio of FC to CYA that's important, not the actual numbers. The pool store one-size-fits-all approach doesn't work. To arbitrarily set a FC level without taking CYA into account is akin to saying someone weighs too much and needs to lose weight without taking height into account.
    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: Tf-100 chlorine drop test inconclusive

    My FC is about 7 right now. My CYA is around 70. "High" is relative. The pool store will tell you 1-3FC is correct and CYA of 50-200 is fine. It's a ratio, not a blanket statement like they make. If you listen to them you will have a cloudy green pool every year, buy more shock and magic potions, dump half your water, and start the merry go round all over. Go by the numbers listed in the FC/CYA chart, and you will steer clear of the pool store initiated problems.


    30K gallon IG vinyl. 1.5HP 2-speed Waterway Mustang pump. 600 lb sand filter. Polaris 280. Circupool SI-60+. TF-100

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    Re: Tf-100 chlorine drop test inconclusive

    Jason,

    enlight me pardon my ignorance, but everywhere I read it states that the recommended FC level is 3-5PPM. Even the chart you referring to is states that CYA levels of 70 shall be supplement with FC levels of 3-5 PPM. Based on your math, CYA level of 70 shall be FC shall be 5.25-8.05 PPM. I am not expert and join this forum to learn, so please explain your reasoning as I am simply questioning the math/formula provided.

    70 x 11.5=8.05
    70 x 7.5=5.25

    Please advice if I am doing the math run, as again I am here to learn.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Mod Squad jblizzle's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    Those % listed before are for a non-SWG pool ... as you can see the 5 and 8 match.

    For a SWG pool, the minimum is little lower at 5% ... but it is perfectly safe to swim all the way up to shock level which is roughly 40%.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Divin Dave's Avatar
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    Re: Tf-100 chlorine drop test inconclusive

    What Jblizzle said is true. My mistake for not recognizing you are using a SWG... the % changes slightly with a SWG.

    In any case though, I think where you are coming from is the long held pool store and industry standard of keeping a 3 ppm FC level.
    Is this why you commented that you think ~6 is too high?

    The pool store folks dont consider this definite FC/CYA relationship that is required to keep your pool not only sanitary, but algae free.
    But then also, they are really not interested in us having a troublefree pool. If everyone had a troublfree pool, then they
    wouldnt be able to sell all the stuff they do, and would be out of business.

    here is some in-depth reading which a scientific look at this relationship.
    Pool Water Chemistry

    Quote Originally Posted by RESISTENCIA13 View Post
    11.5% of 53 (my CYA level) is 5.83. Is it 5.83 a bit high for FC?
    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 !!

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    Re: Tf-100 chlorine drop test inconclusive

    Thanks for the reading and comments much appreciated.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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    Re: Tf-100 chlorine drop test inconclusive

    Thank you all for your replies and sharing your knowledge with me....i have been enlighted and now many things make sense. Like the advice i am getting from my pool store, which most likely was meant for a regular chlorine pool and the high levels of fc with high levels of cya....it makes total sense that the interaction of these two chemicals wil change the recommended levels of each other.

    I cannot thank you all enough, as believe or not this thread helped me make sense of lots of other things happing with my pool. I hope everyone have a great weekend!





    Quote Originally Posted by resistencia13 View Post
    i just tested my water for chlorine levels using the drop test. I tested for fc by adding one heaping scoop of r-0870 powder. The water turned pink as expected. Next i added 5 drops of r-0871 and the water turn clear again.. When i try testing for cc by adding 5 drops of r-0003, the water remains clear, which per the directions of the tf-100 kit it means i have no chlorine. How is this possible? I am confused. Please advice.
    20,000 Gallons, 33.9 x 19.9 free form inground plaster pool 7 feet deep with Spillover Spa, Salt Generator (Fusion Soft),Heat Pump, Single Speed 2 HP Pump, D.E. Filter. Zodicac PDA, IQ900RS Controller.

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