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Thread: CYA levels off the chart?

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    CYA levels off the chart?

    I just purchased a new home and this is my first pool to play with. I had a local company come and open the pool for me on Wednesday the 11th. They told me not to touch the pool for the first week, just let the filter run 24x7. Well, my TFT test kit came yesterday, the 14th, so I decided to check the chlorine level...0. I went and picked up some tablets and put 3 tablets in each of the two skimmer baskets as it said on the directions. About 45 min later I figured I would check the CYA level. Using the TFT kit I got about 3/4 of the way to 100 and couldnt see the block dot.

    Where do I go from here? Should I test again later on to see if that wasn't just a fluke test? Are those levels high enough where I actually need to start replacing water or should I just try and deal with it?
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    svenpup's Avatar
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    CYA levels off the chart?

    I doubt it's a fluke. You can redo the test with diluted pool water. Measure equal parts pool water and tap water (eg 1cup each) and mix. Perform the CYA test with the 50% diluted pool water and double the result. That will give you a better idea if how much you will need to drain.

    Also, those pucks are adding CYA.
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    Re: CYA levels off the chart?

    the pucks were just a last minute thing, I dont have any more and wont be buying any more.

    I guess my main question is, is a CYA level this high going to be a real problem for me?
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    Re: CYA levels off the chart?

    It will be a considerable problem. Your CYA is likely in the 150-200 range so to keep algae at bay you would have to keep your FC in the double digits.

    Do the CYA test as svenpup described and get a better idea what your actual level is. Then strongly consider replacing some water to bring that down.

    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Re: CYA levels off the chart?

    Yes, high CYA is a problem. If it is over 200, you would need to buy your LC (liquid chlorine) by the tanker load to keep your pool sanitized and algae free. Do as suggested and dilute for another test so you will know how much water to replace.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: CYA levels off the chart?

    Quote Originally Posted by gh0st View Post
    the pucks were just a last minute thing, I dont have any more and wont be buying any more.

    I guess my main question is, is a CYA level this high going to be a real problem for me?
    I took over my pool with CYA somewhere in the 220-240 CYA range, and with severe water restrictions, I wasn't able to drain and refill. I had to maintain the pool at that CYA level. So I can say that it can be done. But it is not easy, nor do I recommend it for a number of reasons.
    1) If CYA is 240, minimum FC has to be 18. Target is 18-27. I targeted 24. That is waaaaay above the ability of any tester except the FAS-DPD test. So that tester has to be used every single day.
    2) Maintaining FC at those levels can throw the pH test off. FC above 10 reacts with the reagent and makes it read falsely high. The CYA seems to buffer it, but there's always a doubt about what the pH really is. The only way to really be sure of pH is to let the FC drop below 10 just to test it and pray no algae takes hold in that interval.
    3) If any algae occurs, shock level FC is 94! At that point, it's cheaper to drain the thing and pay the penalties to the water company!

    After I was able to drain and refill, life got much easier. I never doubted the pH test results. I could do a quick check of FC using the color matching test and just dump in the usual amount if it looked right. Algae no longer terrifies me, not that I have ever had any. But if I do get it, it's not a big deal to raise the FC enough to kill it.

    If you're not under drought restrictions, you'd be a fool not to drain and refill. Water is relatively cheap, and if you call ahead, a lot of times you can get the tiered rates or the sewer fees discounted every two or three years for pool filling.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: CYA levels off the chart?

    Like you I acquired a house with a pool and all of the headaches the previous owner left me with. Mine was in good shape except for the CYA, which was 200+ when I took it over. Due to a very high water table I have been bringing it down slowly and am now at 100. Hopefully by the end of this season with drains and backwashes I will get into a more reasonable level.

    As Richard explained, maintaining a pool with high CYA can be done, but it takes staying on top of it.

    If you don't have things going against you, a drain and refill is probably the best bet. If you are ONLY at 200 then you only need to rain 75% to get to 50 CYA.

    Good luck & welcome!
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: CYA levels off the chart?

    Thanks for all the responses. Luckily I dont live in an area with water restrictions. I'm going to take a water sample down the road and see if they run into the same results, that will most likely be the case and I'll have to call in the water trucks :/

    If I wanted to drop the CYA down to 37-ish does that mean I would need to replace 21000 gallons? Am I doing this math right?
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    Mod Squad tim5055's Avatar
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    Re: CYA levels off the chart?

    Quote Originally Posted by gh0st View Post
    Thanks for all the responses. Luckily I dont live in an area with water restrictions. I'm going to take a water sample down the road and see if they run into the same results, that will most likely be the case and I'll have to call in the water trucks :/

    If I wanted to drop the CYA down to 37-ish does that mean I would need to replace 21000 gallons? Am I doing this math right?
    I get 81% or 22,680 gallons

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    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: CYA levels off the chart?

    I don't have much to add other than to say I'm pretty much in the same boat as you. I tested around 200 ppm CYA and the general consensus here is even that measurement can't be reliably trusted given the high amount. I SLAM'ed the pool according to my CYA level and I used A LOT of bleach in the process. I hosted a pool party on Father's Day so now I will be doing water replacement to get the CYA down. I live in a high water table area so I have to do it in steps although I've been toying with the idea of matching filling and emptying rates so that the level stays roughly the same over the water replacement process. I've measured my submersible sump pump's GPM in real working conditions so that I can try to match that with incoming water flow.
    Pool: 19K IG, Vinyl, grecian
    Equipment: Hayward Super Pump (1hp), Cartridge Filter
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    Re: CYA levels off the chart?

    So i have been reading this thread with great interest. Regarding reading CYA levels with the Taylor K-2006 kit...my black dot goes away way before i even get close to the 100....so i was wondering how one even calibrates what their CYA is so that you can do the rest of the calculations for good pool maintenance.

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    Re: CYA levels off the chart?

    There is a 50ppm standard solution available. http://tftestkits.net/R-7065-CYA-Sta...ution-p34.html

    If your dot is disappearing at a higher level than 100, you can dilute your pool water sample with an equal amount of tap water, then test this dilute mixture, and multiply your result by 2.
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: CYA levels off the chart?

    Got it......hate the thought of draining what seems like 75% of the water after getting all my other #'s into a nice area, and shocked the pool and got a FC reading of 30, and worse of the worse, the wife wants to go into the pool this weekend. But if I have to bite the bullet....I guess I need to do it. I'll do that 50% dilution 1st. So I think I read somewhere (been doing so much reading on this great site i get bleary eyed) fill the taylor k-2006 CYA test bottle # 9191 to the 7ml line with pool water, and add tap water to bring up to 14ml, shake to mix, pour out enough water to bring it back to the 7ml, then do the test according to the CYA test procedure, and multiply the result by 2? WHEW...do i got it?? )

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    Re: CYA levels off the chart?

    Yep.

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    Re: CYA levels off the chart?

    I am having problems with CYA test results. Yesterday, I had my pool store to test and they recorded 100. I came home and performed my own and recorded 95. This morning I performed 4 tests depleting the testing agent from 2 bottles!!

    I alternated between 100% and 50% dilution. Two 100% and two 50%,

    Test 1 @ 50%: 30 x 2= 60ppm
    Test 2 @ 100%: 100 ppm
    Test 3 @ 50%: 45 x 2= 90 ppm
    Test 4 @ 100%: 70

    Either the tester or the test or both isn't reliable.....

    Any suggestions on how to obtain the "real" results?

    The CYA/FC chart targets a range for FC at between 7 to 12....depending on which result I use. BTW is FC at 12 safe?

    Other results:
    pH 7.2 (added 19 oz of 20 Team Borax yesterday--no significant change --base demand count to achieve 7.6 went from 10 to 8)
    FC: 6ish...(for 48+ hours-using K2005 kit--K2006 wont arrive until tomorrow)
    CH: 50
    TA: 120

    I just had a thought that I can use PoolMath to determine CYA change based on what I have added. Last week, pool store and my test indicated 50-60, respectively. I have added 2# of Sodium dichloro-s-tri-dih 99%, and the pool has consumed 1 and half 3" (8.7oz each) Tricholoro-s-tri-dih 99%.....So if the poolmath calculator is accurate , I have added 35ppm of CYA in the last week!!!! Indicating CYA of 90-100 if I use the mode of numbers.

    Wow, my ignorance before TFP is remarkable! and most disappointing it is out of character to accept advice without question.

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    Re: CYA levels off the chart?

    Well I'd say it's definitly between 80-100- maybe pick 90 to figure out how much you need to drain. When you mix the solution, you can pour it multilple times into the test tube and see if you can get a consistant number when the dot goes away. Order some more reagent. FC of 12 is safe to swim in.
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    Re: CYA levels off the chart?

    Quote Originally Posted by 7Iron View Post
    I am having problems with CYA test results. Yesterday, I had my pool store to test and they recorded 100. I came home and performed my own and recorded 95. This morning I performed 4 tests depleting the testing agent from 2 bottles!!

    I alternated between 100% and 50% dilution. Two 100% and two 50%,

    Test 1 @ 50%: 30 x 2= 60ppm
    Test 2 @ 100%: 100 ppm
    Test 3 @ 50%: 45 x 2= 90 ppm
    Test 4 @ 100%: 70

    Either the tester or the test or both isn't reliable.....

    Any suggestions on how to obtain the "real" results?

    The CYA/FC chart targets a range for FC at between 7 to 12....depending on which result I use. BTW is FC at 12 safe?
    The results of a CYA test are always just a little subjective due to the ability to see when the dot disappears. I would say just be careful in preparing your test solution and have a couple of people "read" the test. Once the solution is prepared you can pour it back and forth between the bottle and tube over and over to get a better reading. My wife & I will do it a few times to verify our reading.

    Yes, FC of 12 is safe. Due to my high CYA I have been swimming with the FC level between 10 - 15 for a couple of months.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: CYA levels off the chart?

    The most comprehensive article I have found on maximum FC is from the Canadian: National Collaborating Centre for Environmental Health titled "POOL CHLORINATION AND CLOSURE GUIDELINES".

    Even though it is Canadian, they discuss standards of US and Australia, as well as the World Health Org (WHO).

    The following is their conclusion:

    "In conclusion, while there is no specific evidence to support the 10 ppm level used as an upper limit for pool closures based on health effects through ingestion, inhalation, and dermal exposure, animal studies on eye irritation do provide some evidence for the 10 ppm FAC limit. Important factors to consider are the combined chlorine levels (chloramines), to which most of the health impacts are attributed during swimming, and maintaining appropriate pH levels, which affect chloramine production and effectiveness of disinfection"


    I wont give a link, because it may be a violation of the hotlink rule of this forum. But you can Google the article and organization and find it pretty easy.

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    Re: CYA levels off the chart?

    Probably worth mentioning just for completeness that an FC level of 12 is safe at your CYA level.

    With zero CYA the answer would probably be "no, that's too high".

    If you don't acknowledge the impact of CYA then things get a bit confusing. Interesting that the conclusion above mentions that most of the health impacts are attributed to CC levels, not FC.
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    Re: CYA levels off the chart?

    Tim5055, just so i am clear on your post, when you say "Once the solution is prepared you can pour it back and forth between the bottle and tube over and over to get a better reading. My wife & I will do it a few times to verify our reading." do you mean you take the recorded sample out of the CYA vile, put in another container and then put back into the vial to confirm the dot has disappeared?

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