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Thread: Can't keep FC up

  1. Back To Top    #1

    Can't keep FC up

    My pool:
    In-ground gunite
    7700 gallons
    Motorized cover, covered most of the day
    DE filter

    The situation:
    I have a TF100 kit. I tested 2 weeks ago and got a 0 reading for CYA. Previously used 3" pucks to chlorinate so I figured there had to be some CYA in there but maybe it just wasn't reading in the test. Added enough CYA, per poolcalculator, to bring CYA to 20, figured I'd start slow and re-test. I re-tested yesterday and I still get a CYA reading of about 0. The rest of the numbers are:

    3 days ago
    FC: 3.0
    CC: 3.0
    TA: 70
    PH: 7.0, been having a hard time getting this up with borax.
    CH: 350
    CYA: 0, or I can still see the black dot with the tube full, pretty much clear

    Water has been crystal clear until 3 days ago, it was very slightly green. Should have been more diligent with my bleach.

    So I shock. I'm adding bleach as if it had CYA of 20 since I've read on here that sometimes you will have 15 or 20 CYA even with no reading, and since I added granular CYA to bring to 20, I've went with that.

    Add enough bleach to bring FC to 12. I've been trying to re-test as often as I can since I'm at work during the day, but I've been testing in the morning, then mid-morning, then lunch, then mid afternoon, then at night. I've been adding enough bleach to bring FC to 12 each time. Cover has been kept on during the day so I wouldn't lose any chlorine to the sun. The FC has always been between 2 and 5 and the CC has been between 2 and 4. This morning I tested about 6:45am. FC was 3 and CC was 2. I add bleach to bring FC to 12. Test again at 7:45am, FC was 2.5 and CC was 2.5.

    How can it use that much chlorine in one hour? And the CC going up now? I've thought I was doing something wrong with the test but I've followed the directions exactly and have been very careful with everything.

    Oh and after about a day and a half, the pool had no more green tint and is almost perfectly clear, maybe a slight blueish tint. There are no visible signs of the algae anywhere although I know it's not gone yet, right?

    So I'm thinking maybe there's more CYA than is showing on the test and I need more chlorine. I really don't know anymore.

    Oh and I've been running the filter 24/7 while I've been trying to shock. The psi has only went up 1 so far.

    Anyone have any ideas? Hope I haven't forgotten any info that you would need to help. Thanks.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  2. Back To Top    #2
    frustratedpoolmom's Avatar
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    Re: Can't keep FC up

    FC plus CC equals TC.

    If your CC is more than .5, you need to shock your pool, and keep it there until your CC drops to .5. Are you certain you are performing the FAS-DPD test correctly? If you are shocking your pool at night, you want enough bleach to get to 12 FC, and then in the morning you want it to still be at 11 or 12, with a CC of .5 or less. Does that make sense? If you lose more than 1ppm overnight or still have more than .5 CC, you are not done shocking....keep that FC up. Consider adding some more CYA to get it to 30, and then adjust your FC according to the chart. Is this a new pool? Is that why you had no CYA? I'm surprised that with the pucks you didn't have any.....?
    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
    http://www.PerfectlyClearPoolService.com

  3. Back To Top    #3

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    Re: Can't keep FC up

    I have a couple of suggestions. First, on your cc's, they're not going away b/c sunlight (ultraviolet) is the best thing to take them out. Take the cover off and let the sun burn off those cc's! Yes, it will take out your fc's as well, but bleach is cheap.

    Second, add a bit more CYA. Removing the cover during the day to let the sun burn off your cc's is priority, but the CYA will help keep your fc's from being burned off so fast.

    Third, since your pH seems to want to run low, raise your TA a bit, using baking soda or washing soda (soda ash/sodium carbonate). I'd suggest the washing soda since your pH is low also. Baking soda tends to raise TA only and have little direct effect on pH. Washing soda raises both pH and TA. About 100 would be a good number to shoot for on TA.

    Maintaining shock levels of chlorine is priority until your algae and CC's are cleared up. Then you can deal with the other water factors. Good luck!
    ~Jules~

    My pool: INDOOR 13x27 rectangular fiberglass, built ~2001, BBB, TA-60 sand filter, Hayward two speed pump (1 hp/0.33 hp), 3/4 hp booster pump for solar heater
    Taylor K-2006 test

  4. Back To Top    #4

    Re: Can't keep FC up

    Yes I know I need to keep the FC at 12, which is actually one more than the poolcalculator says, just to be safe. And I know the goal is for it not to drop over night, which means the organics are gone. But for 3 or 4 days now I've been trying to keep the FC up to shock levels and after an hour it's back down to somewhere around 3 or 4. It's not a new pool but it is new to me. The previous owner used the chlorine pucks which is why I was surprised as well that it didn't have any CYA according the test. I'm following the directions exactly for all tests. For the FAS-DPD test I fill the chlorine only cylinder to 10ml after rinsing, add 2 regular sized scoops to water, swirl till dissolved, turns pink. Add R-0871 one drop at a time and swirl till it goes clear. Divide by .5, gives FC. Add 5 drops of R-0003 and swirl, turns pink again, add R-0871 till it returns clear, divide by .5, gives CC.

    Not sure what I could be doing wrong. Maybe it has more CYA than my test indicates. I don't have a pool store near by that I could have run tests as well to double check my numbers.

    Thanks.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  5. Back To Top    #5
    frustratedpoolmom's Avatar
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    Re: Can't keep FC up

    Quote Originally Posted by JB426
    Yes I know I need to keep the FC at 12, which is actually one more than the poolcalculator says, just to be safe. And I know the goal is for it not to drop over night, which means the organics are gone. But for 3 or 4 days now I've been trying to keep the FC up to shock levels and after an hour it's back down to somewhere around 3 or 4. It's not a new pool but it is new to me. The previous owner used the chlorine pucks which is why I was surprised as well that it didn't have any CYA according the test. I'm following the directions exactly for all tests. For the FAS-DPD test I fill the chlorine only cylinder to 10ml after rinsing, add 2 regular sized scoops to water, swirl till dissolved, turns pink. Add R-0871 one drop at a time and swirl till it goes clear. Divide by .5, gives FC. Add 5 drops of R-0003 and swirl, turns pink again, add R-0871 till it returns clear, divide by .5, gives CC.

    Not sure what I could be doing wrong. Maybe it has more CYA than my test indicates. I don't have a pool store near by that I could have run tests as well to double check my numbers.

    Thanks.
    My kit instructs ONE heaping scoop of powder. Does my one heaping equal your Two regular?

    Here's a link with pics for the CYA test, you may find it helpful...

    Ok. Lets see. You are adding chlorine, enough to raise you to 12. How soon after adding are you testing? One hour? And it's to 3 or 4? What kind of product are you shocking with? If it's bleach, do you trust it's strength? What brand is it? Possible it's lost it's strength and your not ever reaching 12? Maybe try a different brand or strength and see if that makes a difference? I'm going to guess that you are killing the algae as fast as you add bleach, and you aren't adding enough to reach shock level. Try testing after 30 minutes, and add more to get back to 12....? Guessing here....

    If the drop is during the day, the sunlight will deplete it rapidly which tells me you don't have enough CYA, not that you have more.... this is perplexing isn't it.... so perhaps add more CYA.

    You definetly have a grasp on the process, I can tell by your posts, so it may be something wrong with the chlorine source, or just needs some POP (pool owner patience) in there too? Shock, POP, Shock....LOL sorry wish I had the magic bullet for you. Hope this helps.
    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
    http://www.PerfectlyClearPoolService.com

  6. Back To Top    #6

    Re: Can't keep FC up

    Quote Originally Posted by frustratedpoolmom

    My kit instructs ONE heaping scoop of powder. Does my one heaping equal your Two regular?

    Here's a link with pics for the CYA test, you may find it helpful...

    Ok. Lets see. You are adding chlorine, enough to raise you to 12. How soon after adding are you testing? One hour? And it's to 3 or 4? What kind of product are you shocking with? If it's bleach, do you trust it's strength? What brand is it? Possible it's lost it's strength and your not ever reaching 12? Maybe try a different brand or strength and see if that makes a difference? I'm going to guess that you are killing the algae as fast as you add bleach, and you aren't adding enough to reach shock level. Try testing after 30 minutes, and add more to get back to 12....? Guessing here....

    If the drop is during the day, the sunlight will deplete it rapidly which tells me you don't have enough CYA, not that you have more.... this is perplexing isn't it.... so perhaps add more CYA.

    You definetly have a grasp on the process, I can tell by your posts, so it may be something wrong with the chlorine source, or just needs some POP (pool owner patience) in there too? Shock, POP, Shock....LOL sorry wish I had the magic bullet for you. Hope this helps.
    Wow so I bought the kit from you, cool. Yeah, sorry about that. You got me on the scoop thing. Just wasn't sure I was getting enough in there and I think I read that waterbear here puts 2 scoops. Does this make a big difference in the test, the amount of powder? It seems a heaping scoop is not the most exact either. I can do a heaping scope, though, for sure.

    I've been using walmart ultra bleach and clorox regular, of course both are 6%. Same result. I thought the bleach may be bad as well. Believe me, I've been trying to think of everything. Maybe a little more time is needed. The drop is during the day with the cover on, and at night, so it has to be comsumed by organics. Maybe more sunlight would help burn some CCs as giulietta1 suggests?

    I have seen the CYA test photos before and think I'm doing that one right as well. Fill to bottom of label with pool water, fill to top of label with R-0013, mix and wait at least 30 seconds and then slowly add to tube. Mine never gets cloudy at all.

    I've tested after 1 hour and it's dropped to about 3 or 4, no sunlight.

    I'll try to get some 10% chlorine and try that.

    Thanks a lot for your help.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  7. Back To Top    #7
    frustratedpoolmom's Avatar
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    Re: Can't keep FC up

    Quote Originally Posted by JB426

    Wow so I bought the kit from you, cool. Yeah, sorry about that. You got me on the scoop thing. Just wasn't sure I was getting enough in there and I think I read that waterbear here puts 2 scoops. Does this make a big difference in the test, the amount of powder? It seems a heaping scoop is not the most exact either. I can do a heaping scope, though, for sure.

    I've been using walmart ultra bleach and clorox regular, of course both are 6%. Same result. I thought the bleach may be bad as well. Believe me, I've been trying to think of everything. Maybe a little more time is needed. The drop is during the day with the cover on, and at night, so it has to be comsumed by organics. Maybe more sunlight would help burn some CCs as giulietta1 suggests?

    I have seen the CYA test photos before and think I'm doing that one right as well. Fill to bottom of label with pool water, fill to top of label with R-0013, mix and wait at least 30 seconds and then slowly add to tube. Mine never gets cloudy at all.

    I've tested after 1 hour and it's dropped to about 3 or 4, no sunlight.

    I'll try to get some 10% chlorine and try that.

    Thanks a lot for your help.
    LOL it's not "my kit" I just meant my TF-100 that I bought from TF Testkits.com....Duraleigh, the member on here, it's "his" kit....hehehehe I wish I could take credit for it!

    I'm honestly not sure if one or two scoops makes a difference.... I'm just reaching for anything at this point...

    Yes, I would leave the cover off, it will help on the CC's you'll probably have to add the chlorine more frequently. But with it being the weekend, maybe that won't be as much of a problem. I use the wal-mart bleach and never had a problem, the Clorox should be fine. I was thinking if it was some dollar store off brand or something....

    Well, have some pop and keep plugging away, I'm not sure what else to suggest....
    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
    http://www.PerfectlyClearPoolService.com

  8. Back To Top    #8

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    Re: Can't keep FC up

    JB,

    1. Multiply the drops by .5 on the FAS/DPD chlorine test......don't divide.

    2. As long as the pool water sample turns pink/red, you have added enough FAS/DPD powder.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  9. Back To Top    #9

    Re: Can't keep FC up

    Quote Originally Posted by duraleigh
    JB,

    1. Multiply the drops by .5 on the FAS/DPD chlorine test......don't divide.

    2. As long as the pool water sample turns pink/red, you have added enough FAS/DPD powder.
    Sorry, I meant multiply by .5, or divide by 2.

    I'm just not sure how I get no CYA reading, add the amount of chlorine as if there was 20 CYA, and get all the FC consumed so fast. Water looks pretty much perfect now. Just did the FAS/DPD test again about an hour ago using one heaping scoop and came up with FC 2 and CC 5. How do you like that, I must have some serious organics in there. I guess this weekend I'll add every 30 minutes and see if that helps, and try some 10%.

    Thanks poolmom, sorry, thought you meant your kit, as if you sold it.

    Thanks duraleigh, good to know.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  10. Back To Top    #10
    klavant's Avatar
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    Re: Can't keep FC up

    I added (2)182 oz jugs of bleach every hour for about 8 hrs straight befor the CC cleared up in my pool. You have to set aside an entire day and declare war on the organics. Once it clears, everything shoul dbe fine

    I haven't been to the pool store all season, thanks to the info I learned here.
    Kurt
    _______________________
    9,600 Gal. AG Vinyl
    Hayward C900 Cart filter
    2 speed pump (0.5/2.0 HP)

  11. Back To Top    #11

    Re: Can't keep FC up

    About 11am this morning I left the cover off to get some sun and added more bleach. Checked it at lunch and the CC is now 1.5 and FC is 1.5 too. Added more bleach. Maybe the CC is going down now. I will continue adding bleach and hopefully soon it will be able to hold FC overnight.

    I will be declaring war on the organics full time this weekend.

    Thanks everyone for all the help.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  12. Back To Top    #12
    Casey's Avatar
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    Re: Can't keep FC up

    I don't know how important the shake is after waiting the 30 seconds on the CYA test but I didn't see you post that you shake it a final time before filling the tube.

    All I can suggest is to pound it hard with bleach when you start. Good luck and keep us posted.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

  13. Back To Top    #13

    Re: Can't keep FC up

    Just to let you guys know, I got whatever organics I had knocked out this weekend. Just kept adding bleach and it finally broke the stuff. Just had to add bleach about every 30 minutes for a while then every hour. CC is now zero and FC holds up. Water is perfectly clear. Now I will work on getting my PH up a little and I'll check the CYA again and add if necessary. Next time I shock it will be over the weekend when I can add bleach more regularly, although I hope I don't need to do that again anytime soon. Thanks to everyone.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  14. Back To Top    #14
    frustratedpoolmom's Avatar
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    Re: Can't keep FC up

    Glad to hear your good news!
    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
    http://www.PerfectlyClearPoolService.com

  15. Back To Top    #15
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    Re: Can't keep FC up

    Maybe your CYA test reagent is bad?

    Just an idea... Try dissolving a small amount of granular CYA in a bucket of water then test the water in the bucket. It's turbidity should be very high, and should read very high CYA (100+) I would think...
    Daniel

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  16. Back To Top    #16

    Re: Can't keep FC up

    Quote Originally Posted by Firefly2000
    Maybe your CYA test reagent is bad?

    Just an idea... Try dissolving a small amount of granular CYA in a bucket of water then test the water in the bucket. It's turbidity should be very high, and should read very high CYA (100+) I would think...
    I guess it's possible, I'll try it. Thanks.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

  17. Back To Top    #17

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    Re: Can't keep FC up

    JB,

    Unless you have good reason to believe there is CYA in your pool, my bet is there is none. That same reagent lot # is in more than a hundred kits so I imagine we'd have heard if it's ineffective.

    Anything is possible, but the common sense solution tells me you have inadequate CYA in your pool.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  18. Back To Top    #18
    frustratedpoolmom's Avatar
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    Re: Can't keep FC up

    Quote Originally Posted by duraleigh

    Anything is possible, but the common sense solution tells me you have inadequate CYA in your pool.
    That was my thought too....
    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
    http://www.PerfectlyClearPoolService.com

  19. Back To Top    #19
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    Re: Can't keep FC up

    As far as the two scoops goes, Taylor is the one that says to put in two scoops and if the color does not hold (because chlorine levels are very high) then add additional scoops until it does. What is important is that a stable pink color forms.

  20. Back To Top    #20

    Re: Can't keep FC up

    Quote Originally Posted by duraleigh
    JB,

    Unless you have good reason to believe there is CYA in your pool, my bet is there is none. That same reagent lot # is in more than a hundred kits so I imagine we'd have heard if it's ineffective.

    Anything is possible, but the common sense solution tells me you have inadequate CYA in your pool.
    Yeah, I would think there was no CYA either. But I tested it a while back and came up with zero, so I measured and added granular CYA, per poolcalculator, to go to 20. You know go to 20 first and then I could go to 30. But even after adding the CYA and waiting 2 weeks to make sure it was all dissolved, I still come up with zero on the test. Then I read that CYA levels of 15 or 20 may not show on the test. So I don't know. I can add some more and then test again, I just didn't want to accidentally go too high.
    7850 gallon gunite IG rectangular pool, Anthony DE 52 sq. ft. filter, Anthony natural gas heater, Pentair 3/4 HP 340027 pump.

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