Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: CYA numbers don't jive......

  1. Back To Top    #1
    Circles47's Avatar
    Join Date
    Sep 2011
    Location
    Covington, Ohio
    Posts
    42

    CYA numbers don't jive......

    This spring I opened up the pool to perfection. Numbers were perfect, water was clear, etc. The CYA was right where it was when I closed last fall....at 45. After my initial test, I didn't check the CYA again, because it never reallly changes much. However, my pool care had become a little sporadic, and I should have realized that after I added my initial 10" of water to top off the pool from the winter, my CYA would drop some.

    A couple of times during the last month, my FC dropped to about zero, but after adding more chlorine, my CC still seemed to be less than 1.0. so I never worried much about it. After all, the water was still clear.

    I recently had to go out of country, and knowing it was going to be very warm, and the family would want to swim, I instructed a family member how to run stuff, and told them just to add some chlorine every day until I got back, and then I would fine tune it.

    Well, long story short, a couple of days after I got back, I checked the pool, and to my horror, I had green alae growing all over the bottom. I should have checked all my numbers at that time, but I panicked, and began dumping in chlorine to bring to shock level, and spent the rest of the evening brushing and sweeping.

    For the last 4-5 days, I have kept the pool at shock level, brushing every day, and have been doing an OCLT every night. My last test I went from 18 FC in the evening, to 16.5 the next morning. Last evening after work, when my levels had finally come down to acceptable FC ranges, I went ahead and did a full test.

    The results were:
    FC - 6.5
    CC - 1.0
    PH - 7.5
    TA - 140
    CYA - less the 30, once the tube was full, I could still see the black dot pretty clear. I'm guessing maybe 20?


    I checked the CYA 4 different times, in different lighting, and it always was the same. I tested it with cold water, I tested it with room temperature water, I used different reagent tubes....always the same.
    I'm thinking that perhaps the low CYA is the reason I have been struggling to maintain acceptable FC levels (My neglect not withstanding!)

    But here's my question: Before I go adding more CYA and create another issue, why would it be so low? I know I added about 15% water, and there has been a normal amount of rain, but should it have dropped to under half what it was the first of May? Due to a high CYA level last spring, and a partial dump/refill, I had bought all new R-0013 last year, so this stuff is no more than a year old, and it appeared to be consistent when I checked it in May.

    Is there something I'm missing here??

    Edit: And if the CYA really is that low, I've been shocking the pool with a whole lot more chlorine than needed!

    Thanks for the input!

    Eric
    Sharkline 24' round AG, 15,200 gal, vinyl liner, Hayward Power Flo Matrix 1-1/2 hp pump, Hayward S210T 200 lb.sand filter, Rheem 100 cfh heater

  2. Back To Top    #2

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,084

    Re: Can CYA tester get old?

    I cannot fully explain your loss of CYA but it really isn't important at this point. What is important is that you get some in there.

    If it were my pool, I would calculate and dose enough CYA to get to 30 ppm and assume that is what's in your pool and disregard testing for it for a week.

    Next, you REALLY need to shock the pool properly. read "How to Shock Your Pool" up in Pool School and follow that process TO THE LETTER and your pool will clear.

    Your chlorine applications have been sporadic and inconsistent in the past. BBB is all about precision and careful testing......your pool will stay crystal clear the rest of the summer if you will manage it.

    I have a tendency to be blunt but please don't take it as rude but rather to drive home a point.......If you are to have a crystal clear pool, you must learn to manage your chlorine better.

    PS - The R-0013 reagent is inert and very stable. I have never known it to go "bad".
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3
    BoDarville's Avatar
    Join Date
    Jun 2012
    Location
    DFW, Texas
    Posts
    3,840

    Re: Can CYA tester get old?

    Quote Originally Posted by Circles47
    My last test I went from 18 FC in the evening, to 16.5 the next morning.
    This is an indication that there is something organic living in the pool that is causing FC greater than 1 ppm at night. CYA would have nothing to do with FC consumption at night. Losing more than 1 ppm FC overnight and CC of 1.0 are signs that you need to continue the Shock Process. Since your current FC is 6.5 ppm, I would take this opportunity to lower pH to 7.2 before resuming the Shock Process. I would also raise CYA to at least 30 ppm.

    Quote Originally Posted by Circles47
    Before I go adding more CYA and create another issue, why would it be so low? I know I added about 15% water, and there has been a normal amount of rain, but should it have dropped to under half what it was the first of May?
    No, this is unusual. The water addition and rain will dilute it somewhat, but not to this extent.

    Quote Originally Posted by Circles47
    Due to a high CYA level last spring, and a partial dump/refill, I had bought all new R-0013 last year, so this stuff is no more than a year old, and it appeared to be consistent when I checked it in May.
    This is one of the more stable reagents and should still be OK after a year, but it depends on where you store it. If it's exposed to high heat or sunlight, it might break down sooner than that. Does it have an off-color or is it cloudy?

    Quote Originally Posted by Circles47
    I instructed a family member how to run stuff, and told them just to add some chlorine every day until I got back, and then I would fine tune it.
    "Just adding some" chlorine could be the root cause of the problems you are experiencing. This is the one chemical level that must be managed tightly.
    Gold Supporter, TFP Lifetime Supporter, 26,680 gal Plaster IGP 3.5 - 10' depth / Attached Waterfall Spa, Manually Chlorinated, Triton Sand Filter, 1.5 HP * 1.1 SF = 1.65 SFHP 1-speed Pentair WhisperFlo WF-26 Pump, 400K BTU NG Teledyne Laars Series One Heater, Polaris 360, Test Kit Comparison, Chlorine/CYA Chart, SLAMing Your Pool, OCLT
    A good test kit is an investment, not an expense.

  4. Back To Top    #4
    Circles47's Avatar
    Join Date
    Sep 2011
    Location
    Covington, Ohio
    Posts
    42

    Re: Can CYA tester get old?

    Quote Originally Posted by BoDarville
    "Just adding some" chlorine could be the root cause of the problems you are experiencing. This is the one chemical level that must be managed tightly.
    I know. There was an above average amount of stress leading up to this trip, and I should have instructed more diligently, however, at the time, it was the least of my concerns. This week, I'm paying my dues!

    Quote Originally Posted by duraleigh
    Next, you REALLY need to shock the pool properly. read "How to Shock Your Pool" up in Pool School and follow that process TO THE LETTER and your pool will clear.

    Your chlorine applications have been sporadic and inconsistent in the past. BBB is all about precision and careful testing......your pool will stay crystal clear the rest of the summer if you will manage it.

    I have a tendency to be blunt but please don't take it as rude but rather to drive home a point.......If you are to have a crystal clear pool, you must learn to manage your chlorine better.
    No offence taken, duraleigh. Last year, after my CYA issue, I faithfully tested and adjusted the pool, and it was crystal clear all year. But this year.....I guess I got lazy. As far as shocking it now, I HAVE been doing it according to Pool School. But when I began to suspect that something was amiss, I let my chlorine levels drop below shock so that I could get some accurate test results.

    I've bought some more stabilizer, have it ready to put in, but wanted to be sure before I added it. Still a little skittish from my high CYA issues last year!

    I think it's OK now, but I'll start the shock process again until I'm sure my 3 criteria are met. Meanwhile I'll SLOWLY begin bringing up my CYA until I can read the test.
    Sharkline 24' round AG, 15,200 gal, vinyl liner, Hayward Power Flo Matrix 1-1/2 hp pump, Hayward S210T 200 lb.sand filter, Rheem 100 cfh heater

  5. Back To Top    #5

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,084

    Re: CYA numbers don't jive......

    I'm gonna' revise my advice on CYA....Dose enough to get to 20 ppm....

    That'll be enough for now and still allow you some headroom to use pucks for a couple of days if you go back out of town.

    Wait five days or so before re-testing CYA but assume it is in there and shock accordingly.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6
    Circles47's Avatar
    Join Date
    Sep 2011
    Location
    Covington, Ohio
    Posts
    42

    Re: CYA numbers don't jive......

    Quote Originally Posted by duraleigh
    I'm gonna' revise my advice on CYA....Dose enough to get to 20 ppm....

    That'll be enough for now and still allow you some headroom to use pucks for a couple of days if you go back out of town.

    Wait five days or so before re-testing CYA but assume it is in there and shock accordingly.
    With my test kit only starting at 30 CYA, how would I know when I'm at 20? I KNOW there's some CYA in there, and am assuming it's close to 20 already.....
    Sharkline 24' round AG, 15,200 gal, vinyl liner, Hayward Power Flo Matrix 1-1/2 hp pump, Hayward S210T 200 lb.sand filter, Rheem 100 cfh heater

  7. Back To Top    #7
    Circles47's Avatar
    Join Date
    Sep 2011
    Location
    Covington, Ohio
    Posts
    42

    Re: CYA numbers don't jive......

    Update:

    Stupid algae.

    I've been trying to maintain shock levels for a week. I say trying, because I need to go to work to pay for the chlorine...probably somewhere around 20 gallons by now. Have checked levels on the average of 5 times per day, and adjusted accordingly. Have brushed until my arms ache. Removed steps, enlarged 1/8" holes in steps to 1/2" holes, and filled every single step full of chlorine, as well as the legs, and then submerged it back into the pool. Backwashed filter, added CYA and am now around 25, cleaned all the baskets...and still this stupid, crystal clear pool keeps mocking me with a loss on my overnight tests! Even if I've missed something.... and I can't imagine what it would be.....it's been at shock level for so long surely it would be dead by now.

    Stupid algae....
    Sharkline 24' round AG, 15,200 gal, vinyl liner, Hayward Power Flo Matrix 1-1/2 hp pump, Hayward S210T 200 lb.sand filter, Rheem 100 cfh heater

  8. Back To Top    #8

    Re: CYA numbers don't jive......

    What brand of bleach are you using? I just opened my pool and am using Clorox "new/concentrated" and it's 8.25%. I shocked to 10 ppm yesterday morning, on a relatively cloudy day. A few hours later, I was at 9 ppm and was shocked to see I was down to 3.5 this morning. My CYA is at 20 or less, correcting that this morning, but still, can't believe the loss. My water is clear, just as you say. I just had a lot of debris at the bottom, but that's clear for the most part. Anyway, I'm questioning my bleach. My CC is 0.

  9. Back To Top    #9

    Re: CYA numbers don't jive......

    Let me add, I've been following this website's methodology, and I have had a truly TROUBLE FREE pool for 2 years!

  10. Back To Top    #10
    Circles47's Avatar
    Join Date
    Sep 2011
    Location
    Covington, Ohio
    Posts
    42

    Re: CYA numbers don't jive......

    Tammi, I started out using 12.5%, ran out, and bought some 8.25 locally. I ran out of that too, and bought some more 12.5, which finished the job. I'm not sure if some bleach is less effective than others. I am pleased to say that I finally passed my OCLT the night before last!
    Sharkline 24' round AG, 15,200 gal, vinyl liner, Hayward Power Flo Matrix 1-1/2 hp pump, Hayward S210T 200 lb.sand filter, Rheem 100 cfh heater

  11. Back To Top    #11
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
    Posts
    10,045

    Re: CYA numbers don't jive......

    Quote Originally Posted by Circles47
    Tammi, I started out using 12.5%, ran out, and bought some 8.25 locally. I ran out of that too, and bought some more 12.5, which finished the job. I'm not sure if some bleach is less effective than others. I am pleased to say that I finally passed my OCLT the night before last!
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •