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Thread: Shocking with high CYA levels.

  1. Back To Top    #1

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    Shocking with high CYA levels.

    FC: 1.3
    PH: 7.4
    AK: 165
    CYA: 90
    TEMP: 90F

    I have done a pretty good job with my pool for 3 seasons, this season I ran into some trouble.

    My pool is in the sun all day (10AM to 5PM). I keep the solar cover on when we are not in it.

    I have been having trouble maintaining FC in the water. Most days it was reading 0, even with my SWG running. I brought my water in for eval at the local pool store. They recommended running the pool for longer, upping the clorine %, and adding CYA (I guess I was at 0!). So I brought my CYA to 30ppm (4# stabilizer), set the SWG to 85% (from 60%), and ran the pump for 10 hours. I would get FC in the pool, but it wouldn't stick around.

    Thinking I may have something wrong with the SWG cell, I got out the manual to look for diagnostics. I had a scaling issue earlier in the season, so gave the cell and acid bath (it had some scaling), put the SWG in "boost" mode, and tested the water near the pool return. The FC levels were higher than the rest of the pool, so the SWG cell is making clorine. I called Jandy for help, and they suggested I up my CYA amount to 75ppm, so I added 6# of CYA (now I am reading 90ppm!).

    I did an overnight FC check (not with the suggested kit however) and lost about 1.8ppm FC

    I want to shock the pool, but I am really concerned about the suggested 30ppm. My 9yo is an avid swimmer (wants to be like Phelps), I have a family party in a week, and it's hotter than **** here in N. CA.

    -Can I shock the pool at a lower level, keep it there for longer, and achieve the same result?
    -What is a considered "safe" FC level, both for swimming, and the condition of my equipment?
    -If I bring the pool to 30ppm after dark (say 8PM), how long until the FC level drops to said "safe" levels?

    Thanks for the help everyone... this site ROCKS! I think I am going to put a sticker on Leslie's door!
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

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    frustratedpoolmom's Avatar
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    Re: Shocking with high CYA levels.

    You can safely swim up to shock level for your CYA. The CYA acts as a buffer for the high chlorine level - its perfectly fine to swim.

    What are you testing with?

    If you don't have one of the recommended kits, I would advise you order one.
    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
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    reebok's Avatar
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    Re: Shocking with high CYA levels.

    haha, I want to put a sticker on leslie's door too. actually I would be happy wearing a tshirt that said this website's url, but that's a different story.
    anyway, using about 2/3 of the recommended chemicals (except chlorine) is a good starting point so you don't overshoot like you did with the cya.
    it definitely sounds like you need to shock, and I recommend not using the boost mode on the swg as it will shorten cell life. you also can't shock with an swg just cause it takes so long, etc. use bleach or liquid chlorine if you can get it.
    do you have a CC or TC reading? what are you testing with?
    a lot of people here will swim up to shock level. so for 90ppm that would be more like 35 than 30. I recommend you erad the chemistry articles in pool-school/ as well as pool-school/water_balance_saltwater_generator

    dang, fpm won this race.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  4. Back To Top    #4
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    Re: Shocking with high CYA levels.

    Quote Originally Posted by ciberspyder
    FC: 1.3
    PH: 7.4
    AK: 165
    CYA: 90
    TEMP: 90F
    first read this:
    water-balance-tips-for-a-swg-t3663.html
    The pool school article is a chopped down version of my original post. I wrote both.

    Second, don't lose any sleep over a CYA of 90. You are fine. I often run mine that high during the summer here in FL.

    If you need to shock I would try adding enough liquid chlorine or bleach to raise the FC 20-25 ppm (with the swg running normally) and then letting it drop. I think you will find it solves your problem. Shocking with the SWG is not effective and can actually work against you. Reasons are technical so I won't go into them now.
    Personally, I would swim once the FC was below about 20 ppm. Remember to NOT cover the pool while shocking since sunlight is part of the process.

    You want to eventually adjust the SWG to maintain about a 4-6 ppm FC level. I would shoot for the upper end and then lower it a bit if you want. If you start getting any problems such as cloudiness or chlorine not holding shock and then maintain the pool at the higher FC that did not have problems.

    YOU NEED TO LOWER YOUR TA!!!!!!!!! NO IFS, ANDS, OR BUTS! 165 PPM IS WAY TO HIGH FOR A POOL WITH A SWG!
    What is your calcium hardness? You mentioned that you had a scaling problem and this is caused by high CH, TA and pH so with a SWG you really need to follow the advice in the first post I listed (Your very low CYA was also a contributing factor to the scaling but was just one part of the equation).
    to lower your TA read this:
    how-to-lower-ta-t5341.html

    What kind of test kit are you using? If your test results are suspect in any way (and I suspect they are) then you need to get a good test kit. IF you are not using an FAS-DPD test or a colorimeter how are you getting an overnight loss of 1.8 ppm? No other testing methods have this kind of resolution. If you are using strips in a strip reader the results are bogus, period!

    some other people on the forum might disagree with some of my advice or not understand why I recommended some of the things I did but if you follow it I think you will find it works.

    If you decide to add borates read this:
    so-you-want-to-add-borates-to-your-pool-why-and-how-t4921.html

  5. Back To Top    #5

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    Re: Shocking with high CYA levels.

    Thanks Guys, helps a lot.

    I don't usually shock with the SWG, only did it to verify that it was making clorine.

    I am testing the PH and AK with an All Clear kit, but I am out of CL reagent, so I used test strips and an AquaCheck read for the FC number, it doesn't give numbers for CC, and TC.

    CYA levels are from test strips that Leslie suggested the last time I was there. My local store doesn't like to sell reagent kits. I think it keeps ppl from bringing thier water in and buying stuff.

    I am going out today to get a better test kit.

    Thanks again!
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

  6. Back To Top    #6
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    Re: Shocking with high CYA levels.

    Make sure you get a kit that includes the FAS-DPD chlorine test and NOT a DPD chlorine test. This limits you to a Taylor K-2006 (NOT the K-2005) which is usually not stocked but must be ordered over the internet or special ordered from a pool store, the TF-100 (internet only), or the Chlorine FAS-DPD Service Test Kit (Leslies branded Taylor K-2006 and NOT usually stocked in the stores but must be ordered over the net).

  7. Back To Top    #7

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    Re: Shocking with high CYA levels.

    I have been reading the suggested docs for a couple days, problem is, all of the numbers in my pool that are off are hard to adjust.

    I am working on lowering TA. It was highter (190).

    My CH is about 300ppm, I would like to get it lower, but we are in the middle of a drought in CA, so draining\refilling isn't very popular right now, is there another way?

    I bought the stupid AquaCheck reader out of desperation. Leslie told me the liquid kits were not as accurate as the test strips and I didn't have anything else to go on. I have been questioning the accuracy anyway, which is why I started reading PH and AK with the stuff I had left in my liquid kit, but I am out of clorine reagents.


    Wish I could get my 50$ back.
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

  8. Back To Top    #8
    reebok's Avatar
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    Re: Shocking with high CYA levels.

    your CH is perfect. pool-school/recommended_levels
    too bad about leslie's nonsense. have you tried returning it?
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  9. Back To Top    #9
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    Re: Shocking with high CYA levels.

    Quote Originally Posted by ciberspyder
    I have been reading the suggested docs for a couple days, problem is, all of the numbers in my pool that are off are hard to adjust.

    I am working on lowering TA. It was highter (190).
    This is your first priority, IMHO! You are gong to need about 3 more gallons of acid to get your TA down but remember not to drop the ph below 7.0. The better you can aerate, the faster the process. You might want to invest in one of those floating fountains that connects to the return. They are not that expensive and well worth the money for lowering TA.
    My CH is about 300ppm, I would like to get it lower, but we are in the middle of a drought in CA, so draining\refilling isn't very popular right now, is there another way?
    Once you get your TA down to the recommended range your CH at 300 is perfect (actually a bit low!) so don't change anything but get the TA down.
    I bought the stupid AquaCheck reader out of desperation. Leslie told me the liquid kits were not as accurate as the test strips and I didn't have anything else to go on. I have been questioning the accuracy anyway, which is why I started reading PH and AK with the stuff I had left in my liquid kit, but I am out of clorine reagents.


    Wish I could get my 50$ back.
    Get either a Taylor K-2006 or a Troublefree Testkits TF100. You will NOT regret it. Also, pick up some AquaChek salt test strips. As far as the strip reader goes, chalk it up to a learning experience. You might want to put it on eBay or Craigslist to try and recoup some of the money.

  10. Back To Top    #10

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    Re: Shocking with high CYA levels.

    I have to tell you guys, the recommended Tayler test kit is AWSOME! It turns out my local Leslie pool had some in stock. I wish I had known about this kit when my pool was installed, no guessing, just numbers. I really like making decisions based on measurable fact, instead of color matching and guessing.

    I took FC measurments, and it turns out I actuall have 6.0 FC and 1.0 CC. So I guess I am holding onto more clorine than I thought I was! I would have been adding clorine for days, for no reason.

    FC: 6.0
    CC: 1.0
    PH: 7.2
    TA: 140ppm
    CH: 300ppm
    CYA: 90ppm

    Thanks again guys!
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

  11. Back To Top    #11
    reebok's Avatar
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    Re: Shocking with high CYA levels.

    you know that you need to be shocking if your cc is 1 right?
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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    Re: Shocking with high CYA levels.

    Yea, I am still going to shock the pool tonight.
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

  13. Back To Top    #13
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    Re: Shocking with high CYA levels.

    Shock as I outlined before. It should do the trick

  14. Back To Top    #14

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    Re: Shocking with high CYA levels.

    Hey guys,
    I think I have the chlorine taken care of. The chlorine smell was pretty strong for a day, but it's gone now, and the water is clear.

    Now I can't get my TA down. I have been adding enough MA to bring the PH from 7.2 to 7.0 for a couple days (usually about 2p at a time), but the TA is sticking at 150ppm, and doesn't seem to be dropping. I have a fountain in the pool, my kids have been jumping\splashing and my SWG has been running, and it still takes forever for the PH to rise. I thought a high TA made the pH rise faster. I am trying to wait for the PH to get to 7.5\7.6 before I add more acid. Should this be taking this long? Could something be affecting my TA\PH reading?

    Thanks...

    FC: 7.0
    CC: 0
    PH: 7.3
    TA: 150
    CH: 350
    CYA: 90
    15,000Gal IG Gunite\Color Quartz Plaster
    Jandy CL460 Cart Filter (460sqft, 150GPM)
    Hayward EcoStar SP3400VSP
    AquaPure 1400 SWG

  15. Back To Top    #15
    reebok's Avatar
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    Re: Shocking with high CYA levels.

    a couple days is nothing. get a bottle of POP and consider making a good aerator if you want it to go faster. here is an example:
    my-aerator-t7799.html

    high TA can make your ph rise faster. but is it doing that in your pool? have you tracked it? lowering TA is only an option, you don't have to do it at all.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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