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Thread: Dissapearing FC and high CYA

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    Dissapearing FC and high CYA

    Hi Everyone! We just bought this house with an awesome pool. We've tried calling a few pool cleaning companies, but can't get a call back or have been flaky, so we've decided to tackle it ourselves. Problem is we have extremely high CYA. Using a taylor test kit the previous owners left us, shows the levels around 170. The FC is also at 0, although we added an hth super shock treatment yesterday morning. 3 1 lb bags with CALHYPO at 56.44% We also have a tablet feeder attached to the pump/filter that I restock with tablets every few days. I can't really justify draining the pool while we are in a severe drought. Any ideas or thoughts? Let me know if more info is needed. Thanks!
    28,000 Gallons IG Plaster
    Cartridge Jandy Model CL460
    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
    Taylor test kit

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    Mod Squad jblizzle's Avatar
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    Re: Dissapearing FC and high CYA

    Welcome to TFP!!!

    No point in trying to clear up the pool until you get the CYA level MUCH lower. Your first step has to be replacing water to get the CYA well below 100ppm ... ideally around 50ppm. If you try to follow the ShockLevelAndMAINTAIN Process to clear up the pool with a CYA of 170ppm (explain how you got that level), then you would have to maintain the FC at 67ppm which is above even what the recommended FAS-DPD chlorine test should reliably read.

    Do NOT use cal-hypo as your CH level is likely already too high (which also required water replacement). You need to only use liquid chlorine.

    I would also suggest you make sure you have one of the Recommended Test Kits.

    How much Pool School have you read? Start with these:
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    Recommended Pool Chemicals
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    Re: Dissapearing FC and high CYA

    I got the 170 ppm level by diluting the pool sample with tap water and then testing the normal way. I found the instructions on here. With only about a month or so of swimming weather, would it be ok or safe to just add the liquid chlorine (how much?) It would be much easier to do the draining in the winter. We were also considering switching to a SWG then as well. I have read some of the Pool School stuff, just trying to make heads or tails of this new adventure! Thanks for the reply!
    28,000 Gallons IG Plaster
    Cartridge Jandy Model CL460
    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
    Taylor test kit

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    Mod Squad jblizzle's Avatar
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    Re: Dissapearing FC and high CYA

    According to PoolMath, the minimum FC level that would have the water be safe (assuming you can see the bottom of the pool) would be 13ppm. The problem is when the FC > 10ppm, the pH test is not valid ... so that is a bit of a pickle. And that is the minimum to maintain AFTER the pool was cleared up and sanitized.

    What does the water currently look like?
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    Re: Dissapearing FC and high CYA

    The weird thing is that the pool looks amazingly clear. Here is a pic...
    28,000 Gallons IG Plaster
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    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
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    Mod Squad jblizzle's Avatar
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    Re: Dissapearing FC and high CYA

    It can look fine, but not be safe from a disease transmission point of view.
    Jason, TFP Moderator
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    Re: Dissapearing FC and high CYA

    Yeah, disease is no good. So based on the calculator, I should drain around half of the pool? Here a link to the https://onedrive.live.com/redir?resi...nt=photo%2cjpg
    28,000 Gallons IG Plaster
    Cartridge Jandy Model CL460
    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
    Taylor test kit

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    Re: Dissapearing FC and high CYA

    You should start there, but realize with CYA of 170, that only gets you to 85.

    Nobody mentioned it, but if you keep using those tablets, your CYA is going to continue to go up. You must go on a liquid diet, or install a salt water chlorine system.
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    Re: Dissapearing FC and high CYA

    You're stuck because there really isn't a way around lowing that CYA level without dumping a lot of water and diluting whats left. There are two main options. One is using a really big tarp over the pool and adding fresh water into the tarp into the pool as you're pumping out the old stuff from under. The advantage to this is it's pretty much a one for one exchange and if water is expensive or scarce it can pay for itself.
    The other way is to add fresh cool water into the bottom of the deep end and pump water out with a portable pump, sump pump ... from the shallow end at the same time. The weight of the cooler water will to a point help separate it from the water you're pumping out but it still mixes some.

    If there was another way we would tell you as we all know the pain in the butt it is to throw away that much water. With a high CYA level it's what you have to do if you want to get any control of your pool. Even a pool company is going to tell you the same thing or if they don't they shouldn't be touching your pool as they can't really control your chemistry with the water as is.

    Chlorine tablets and granular chlorine will contain some CYA almost always. Please don't add any more of that stuff to your pool or you'll start going above 200ppm CYA shortly. You want to start to use only liquid bleach or liquid pool shock (bleach) as a chlorine source as it will not raise your CYA. It's likely also cheaper so that's the good side.

    Once the CYA is down to 70 or less would be even better you need to SLAM the pool. It's like shocking except you only need to do it once and then just maintain your pools chemistry instead of weekly blindly tossing in bags of shock to try and keep the water from turning green.

    You need to keep reading the Pool School articles and the recommended chemicals. You'll see our way is not the pool store way and it's likely not the way the pool guys you're trying to hire would do it. The SLAM takes some time and patience but after it's over our way is easy and much cheaper that running to the pool store and buying an armful of chemicals. In a few weeks you'll actually understand what does what and why you are adding it and what to avoid like algaecide.

    You will need to buy a good test kit and that's the beginning of tuning the water sparkling blue and having a sanitary pool to swim in and enjoy.
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    Re: Dissapearing FC and high CYA

    Not having a SWG, your cya really should reduced to 50.
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    Re: Dissapearing FC and high CYA

    You've gotten some good advice, but I disagree with kiss4afrog. You really need to get your CYA down to 50. The higher the CYA, the more you will spend on bleach. Better to bite the bullet and drain now.

    You can bring it down to 70 only if you are going to install a SWG.
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    Re: Dissapearing FC and high CYA

    Actually you are agreeing with me. The OP stated that in his area they were having a "severe drought". I took that into consideration in my answer. He was talking about draining half the pool which would only get him down to around 85 if he drained and refilled. He was hesitant about draining this year so I didn't want to scare him off (yet) so I'm just being generous about setting a minimum goal of 70 before thinking it would be feasible to SLAM. What I said was "Once the CYA is down to 70 or less would be even better" and the "less would be even better" is the recommended range of 30-50 but that's a lot of water to take out.

    All I'm saying is if it was my pool I would drain until I was at least down to 70 no matter what it cost or took to do it to get control over the chemistry. Once down to 70 he can decide to let it go the year and get it down to 30-50 next year as long as we can convince him not to add bags of shock or tablets that add CYA and hopefully water won't be in as short of supply too. 70ppm CYA isn't a magic number it's just a minimum recommendation in his situation.
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
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    Re: Dissapearing FC and high CYA

    Mrcoolguy,

    If you don't want to drain and replace water, then you might consider using a reverse osmosis treatment. You'd have to do some Google searching to see if there is an RO service company in your area. RO will remove EVERYTHING from your water - CYA, Calcium, salt, etc

    Typically RO is more expensive than water replacement even in areas with high water costs (southwest). But, since your CYA is soooo high and you don't like the idea of dumping water, RO is an alternative if it is available.....an expensive alternative....

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    Re: Dissapearing FC and high CYA

    I really appreciate all the advise! You guys are bringing me around to the idea of draining the pool. I also bought some bleach in the meantime and will stop using the tablets and powder. We do want to install a SWG and probably plan on doing that over the winter when the pool is not in use. What a great community you guys have! Thanks again!
    28,000 Gallons IG Plaster
    Cartridge Jandy Model CL460
    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
    Taylor test kit

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    Re: Dissapearing FC and high CYA

    Whatever way you go, you will have to deal with the high CYA.
    Pool size: 24000gal inground Vinyl-Taylor k-2006 and k-1766 test kits and-speed stir
    Intermatic P1353ME digital timer w/freeze sensor
    CircuPool Si-45 SWCG System
    Polaris 280 vacuum/Polaris PB4-60 boost pump
    Pentair IntelliFlo VS 3hp Pump--Pentair sand filter

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    Re: Dissapearing FC and high CYA

    Just wanted to thank everyone who responded! I was able to drain my pool a few times and the CYA now sits around 70. I was able to successfully SLAM the pool, (0 CC, Clear water, passed the overnight test) and the pool hasn't looked better! Thanks again!
    28,000 Gallons IG Plaster
    Cartridge Jandy Model CL460
    Jandy PlusHP Pump Model PHPM 2.0
    Booster pump model LA01N attached to vacuum
    Taylor test kit

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    Re: Dissapearing FC and high CYA

    Now it's time to fine tune your chemistry and spend some time enjoying your pool rather than battling it !!
    '70s IG Vinyl 32K gal, Lazy L, Hayward SuperPump 1.5hp 120V, S240 Sand Filter W/DE
    Solar Blanket, Well Water, Borax Added, TF-100 tester. ? too cold
    1979, 275gal Conway Emerald Spa P-100-2, ES-2 Spa Pack, bromine floater, indoor
    TF-100, Best test kit - TFTestkits.net
    Please help keep the lights on, become a TFP Supporter!

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