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Thread: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

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    Default Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    ***
    I'm starting a new post to keep it focused. Including the most relevant previous replies to the topic:

    Quote Originally Posted by BigDave View Post
    I'd like to point out that one major difference between your pool water and the bleach sample is the bleach has no CC and your pool clearly does. Perhaps the slow return of pink during the pool water test is some of the CC becoming FC without the reagent you add before the CC test. If this is the case, your CC is realy quite higher than you are presently measuring. I've read many if not all of your posts (and I'm not going to re-read them) and I don't think you've actually gotten your FC to shock level and held it there (if this is wrong, I'm sorry). This could be exacerbating the situation. You keep adding chlorine and producing CC but you never get the level high enough to clear up the CC.

    You could test this with a bucket of pool water say about 4 gallons. Add 1/2tsp of your self certified 12.5%. Should bring your FC up about 20ppm. Stir. Measure FC and CC stopping the FC test the first time it goes to clear.
    Quote Originally Posted by BigDave View Post
    JJB, ... Take it easy, see if you can clear up the CC in a bucket, then you'll know you can clear your pool.
    Quote Originally Posted by JuJuBee View Post
    Thank you so much Big Dave! You are exactly right, I have NOT reached shock level once...in spite of all the chlorine I have used. This link shows my most recent attempts to do just that: http://www.flickr.com/photos/50351313@N03/7260036226/ Thank you for giving me something to try to get a clearer test result. I'll follow it and post the results as soon as I can.
    Results of bucket testing below.

    Quote Originally Posted by chem geek View Post
    Do you have a pool cover that is dark or opaque? **NO** If so, uncover your pool at least part of the day to let sunlight on it as that can help bring down the CC.

    I don't know why the FAS-DPD chlorine test isn't giving you clear readings. Though sometimes the water gets a little cloudy during the test, the color transition is usually pretty clean. See this link and click on "Pool/Spa" on the left, select the K-2006 "To Test (Free and Combined Chlorine) using FAS-DPD". **I watched this the day after receiving kit in April and then again the week after. I'm using same technique as video but with different result. Hour long phone support with Taylor didn't solve anything.

    By any chance was your pool converted from a different type of sanitation such as Baquacil/biguanide/PHMB? There may be something in your pool causing interference with the FAS-DPD test. ** Nope, we built it 5 years ago and the pool company opened/closed (incl. this April.) each year. We maintained & spent >$1000.00 year on weekly use of Bioguard's silky sticks, dichlor, easy shock & swim, Pool Perfect + Phos Free and Inhibit Back Up algae preventative; occasional use of pH up, pH down, clarifier, and Off the Wall cleaner. Products worked well, but had to use constantly and expensive. Also had to battle bouts of cloudy water, low pH or high pH, and constant low chlorine. First four years the TA was always >200
    Thank you both Big Dave and Chem Geek...

    Past 48 hours (CH 400? CYA 70 - 80, Borates 40 but now 50) :

    5/24
    9:45pm --FC 4.0 --CC 1.5 --pH 7.6 --TA 133 --Added 4 gallons 12.5% and 1 full box Borax

    5/25
    7:15 am --FC .5 --CC 1.5 --pH 7.4 --TA 104
    7:40 am Added 3 gallons 12.5% and 1/2 box Borax
    11:20 am --FC 4.5 --CC 4.0 --pH 7.6 --TA 126
    11:30 am Added 3 gallons 12.5% and remaining 1/2 box Borax
    3:05 pm --FC 6.5-7.0 --CC 3.0-3.5 --pH 7.6 --TA 148 --Borates 50! yay
    ----------Added 2 gallons 12.5%
    3:30 pm Added 2 lbs 10 oz. Borax
    4:30 pm --FC 17.5 --CC 3.5
    6:00 pm --FC 11.0 --CC 3.5
    10:00 pm --FC 5.0 --CC 3.0 --pH 7.6
    10:30 Added 4 gallons 12.5% and 1 full box Borax

    5/26
    8:00 am --FC 18 --CC 3.0 --pH 8/8.2? --TA 175 --Added 1 1/2 gallons 12.5%
    10:30 am --FC 25 --CC 2.5

    All tests above maintained the clear after first appearance. None behaved the way all my others had. Possibly because I bombarded the first one with 4 gallons of bleach after considering BigDave's theory of the CC changing to FC and kept slamming it over and over?? But I still have the CC.

    5/26 10:30 am Bucket Test - --FC 56? --CC 3.0
    ...since our FC was already 25, the FC test kept bleaching out with DPD powder. Did it again and kept adding a level scoop until the pink stayed after swirling. (since the level is over 50ppm, not sure if test is accurate...) I also re-experienced my normal testing patterns of the sample slowly returning to blush. Stayed with BigDave's direction of "first time it's clear" and moved on to CC test. Both FC/CC tests resulted in cloudy/clear - never clean. (I notice that happens when I have to use extra scoops of DPD powder.)

    I'm going to wait until I hear back from you before trying the bucket test again.
    I'm wondering how I can have 25ppm FC and still have 2.5 CC, how the bucket can have over 50 ppm FC and still show 3.0 CC, and whether or not we wasted money for the past 2 weeks by using too little chlorine causing us to always need to add so much more???? (We've spent over $200 in chlorine bleach (since April 17th) and have about 10 jugs of the 12.5% left right now.)
    32x16 IG 18K vinyl Grecian; all Hayward equipment: S244T sand filter; .75HP Super Pump; Booster Pump 5060 & Viper; H250IDL2 Heater; CL200 feeder; PF:6.5

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    Default Re: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    I'm sorry, I missed something. Your FC in the bucket test started at 25ppm? and 1/2tsp 12.5% bleach got you to 56ppm? or - ah, I see. You started the bucket test after your 10:30 reading today - right? OK I suppose I wasn't clear - I'm sorry - I gave you the bucket test to save you from using full doses on your pool so you could see that you can clear the pool if you keep at it. I expected to get your bucket to the 20-30ppm FC level, 60 is alot. But since you've already got the pool to 25ppm FC, dump the bucket in the pool and rinse it out. If you start to lose faith that this will work and you don't want to spend so much on bleach to prove it, we can fill it again.
    Be careful with that bucket, it's got alot of bleach in it.

    Do not try to bring your pool to 56ppm FC.

    To clear the CC you have to maintain shock level, not let it drift down. Since you're there now, keep it there. Eventually, you'll oxidize all the stuff in your pool that's showing up as CC, the CC will go to 0 and you'll start keeping FC overnight.

    Really you will.

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    Default Re: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    "Clear" for the FAS-DPD test means clear of color, not that it is clear and not cloudy. When I do the FAS-DPD for my pool water, it is sometimes cloudy after adding DPD powder, especially if the water is warmer. What you are looking for in the test is the absence of pink/red color.

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    Default Re: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    Quote Originally Posted by BigDave View Post
    I'm sorry, I missed something. Your FC in the bucket test started at 25ppm? and 1/2tsp 12.5% bleach got you to 56ppm? or - ah, I see. You started the bucket test after your 10:30 reading today - right?
    Yes, We added 1 1/2 gallons chlorine at 8:00 am. (or FC was 18 and CC was 3.0) At 10:30 our pool was 25 FC and 2.5 CC. That's the water we took and added to the bucket. So when I added 1/2 tsp to the bucket, the bucket's reading was FC 56 & CC 3.0.

    I realized what I did and I should have taken the water before 8:30. So I let it sit in the bucket undisturbed, mixed it again at 1:30 and took another reading where FC fell to 45 and CC 2.5
    .
    Do not try to bring your pool to 56ppm FC.
    I don't try to ever go above 28ppm FC.
    To clear the CC you have to maintain shock level, not let it drift down. Since you're there now, keep it there.
    What about over night? What if it dips below shock level tonight? And with company coming tomorrow night to swim, I'll probably have to work to get it back up to shock afterwards since I need to let it drop low enough to safely swim, correct?
    Eventually, you'll oxidize all the stuff in your pool that's showing up as CC, the CC will go to 0 and you'll start keeping FC overnight.

    Really you will.
    After all I've learned and seen so far, I believe everything you say. Since I couldn't reach shock levels for 2 full weeks, I was worried I was doing something wrong to prolong our agony. Which raises that question again, how can I reach shock levels again without it taking 2 weeks if I am basing it on current FC level, desired level of 28ppm and the poolcalculator's math? That's what I did for the past two weeks.
    32x16 IG 18K vinyl Grecian; all Hayward equipment: S244T sand filter; .75HP Super Pump; Booster Pump 5060 & Viper; H250IDL2 Heater; CL200 feeder; PF:6.5

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    Default Re: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    This is why we emphasize measurement - treatment - measurement - treatment - .... Tools like The Pool Calculator can help with ranging but does not model everything that may be or is in your pool. So, if you need to let it slide to be comfortable having guests in your pool, you know you can get it back with bleach, patience, and perseverance.

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    Default Re: Can't clear CC or reach an FC level after tons of bleach - FAS-DPD testing

    Quote Originally Posted by BigDave View Post
    This is why we emphasize measurement - treatment - measurement - treatment - .... Tools like The Pool Calculator can help with ranging but does not model everything that may be or is in your pool. So, if you need to let it slide to be comfortable having guests in your pool, you know you can get it back with bleach, patience, and perseverance.
    I was able to get it back quickly. With everything being monitored the BBB way, I now can achieve results much faster than the first time. Just another brick added to my new wall of BBB confidence.
    32x16 IG 18K vinyl Grecian; all Hayward equipment: S244T sand filter; .75HP Super Pump; Booster Pump 5060 & Viper; H250IDL2 Heater; CL200 feeder; PF:6.5

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