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Thread: CYA/FC chart making me nervous

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    CYA/FC chart making me nervous

    I am new to the forum. What brought me here was a recommendation of a friend when I told him that I have been using chlorine tabs and my CYA is really high. I am trying to avoid draining my pool. The CYA is testing around 110 and my local pool store told me that it was OK. My chlorine tested at 5.7 and they are telling me that is OK as well. However, they are saying I should be in that range ideally. The CYA/FC chart states my FC should be closer to 12 or so. That seems so high but the explanation makes sense. I don't want to have to replace water to lower by CYA but raising my chlorine to 12 makes me nervous. As a side note, I bought bleach and am not planning on using chlorine tabs any more. Thanks in advance.

    Jason
    10,400 gallon/above ground pool/sand filter

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    Butterfly's Avatar
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    Re: CYA/FC chart making me nervous

    Sorry you are feeling nervous about the CYA/FC chart. But, you kinda have two choices that you have already mentioned. And then there is the RO treatment available in some areas.

    I also would like to know how they measured CYA at 110. The kit tests to about 100 and then is skewed past that. So, it could be 110 or 210. If you do your own CYA test, you could do a 50/50 mix with pool water/tap water (multiply result X 2) and get a good idea if CYA is closer to 100 or 200.

    The bottom line is this. If you do not maintain the FC level based on CYA level, the evil green monster will start growing in your pool.

    Good on you about the tabs
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    Re: CYA/FC chart making me nervous

    Hello Jason, welcome to TFP!

    Your friend is correct - your CYA is high. Unfortunately, the only way to lower that is with a partial drain.

    Pool stores are notorious for poor test results (and poor suggestions based on the readings). A retail store doesn't want to tell you your CYA is too high because of those chlorine tabs, because they were the ones that have been selling you the tabs all this time.

    Basically, if you stick to the recommended levels on this website, your pool will be in the best shape. I know it is a pain to drain and refill, but you can do it a little bit at a time. And once you get your levels in the correct range, you will be set. Better to learn from something sooner than later...and avoid future problems!

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    Isaac-1's Avatar
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    Re: CYA/FC chart making me nervous

    As others have said you have 2 options, just be aware if anything ever does start growing and you have to shock your pool to stop an algae bloom then it will be very hard and costly to do at a CYA level of over 100 (200?). All things considered you will likely have an eaiser, and less expensive time maintaining your pool if you can drain off and refill at least half your water.
    Ike
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    Re: CYA/FC chart making me nervous

    According to the 2x w/tap water test it is closer to 160. But, I have the Walmart (HTH) test kit. I know I need to get a better kit. I really want to be able to swim for Memorial Day weekend. Should I assume the 160 is close or should I get the better kit before I decide how much water to drain. Also, is there any danger of a collapsing pool or something if I drain 50% of my water? What a nightmare.
    10,400 gallon/above ground pool/sand filter

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    Mod Squad jblizzle's Avatar
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    Re: CYA/FC chart making me nervous

    The dreaded puck strike again ... seems like there should be a promotional low-budget movie made for TFP.com with a giant puck crashing in and ruining people's pool parties

    Sorry for the tangent

    While a better test kit would be good, you are likely close with the 160ppm which as you know is WAY too high. According to the poolcalculator.com, your normal FC levels would need to be 12-19ppm and you shock level is 35ppm.

    How does your water look? If it is crystal clear and you have no reason to expect algae, you can use bleach to maintain your FC > 12ppm and swim this coming weekend and deal with the water change next week. Although it is going to be tough if your test only goes up to 5ppm. You could try to use 33% pool and 66% distilled water for your FC test and triple the reading while waiting for your test kit.

    FYI, if you order the TF-100 today, I would almost bet you would have it on Thursday, definitely by Friday. And then you could check your levels before the weekend.

    I am not sure how much of an AGP you can safely drain at once. I know with liner pools I have read to keep at least 1 foot of water in the shallow end to avoid the liner from shifting.
    Jason, TFP Moderator
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    Re: CYA/FC chart making me nervous

    Let me ask you this. How come my neighbor, who has the identical pool as I do and has had it for longer, and uses pucks, has never had this problem?
    10,400 gallon/above ground pool/sand filter

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    Re: CYA/FC chart making me nervous

    Oh, the pool looks perfect, by the way. And thanks so much for all the advice.
    10,400 gallon/above ground pool/sand filter

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    Re: CYA/FC chart making me nervous

    I am guessing he is secretly changing more water than you.

    In reality, in your climate with a shorter swim season and partial drains for winterizing and water replacement due to rain/snow, many people successfully use the pucks as all the water changes keeps the CYA level low enough to maintain.

    Has your neighbor recently tested for his CYA level? Maybe ask if you can test it out of curiosity. If it is a lot lower than yours, try to find out what he is doing differently than you ... in inquiring minds want to know
    Jason, TFP Moderator
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    Re: CYA/FC chart making me nervous

    I just asked him and it was 60. We do mostly the same things. I think he shocks his pool on a regular basis, which I have never done and uses "blue water" crystals on a regular basis as well. I have no idea what those do. The only different is my pool in in partial shade some of the day and his is not. I didn't think that effected CYA at all but obviously I don't get any of this stuff.
    10,400 gallon/above ground pool/sand filter

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    Re: CYA/FC chart making me nervous

    and my pool came with a Nature2 Express. His did not. Sorry, I forgot to mention that one.
    10,400 gallon/above ground pool/sand filter

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    Mod Squad jblizzle's Avatar
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    Re: CYA/FC chart making me nervous

    How did he come up with 60? Pool store? I would still see if you could test it yourself to do a direct comparison to your pool.

    The shocking will not reduce CYA and could in fact raise it depending on the type of chlorine he uses. I do not know what the blue water crystals are.

    Are you actually using the Nature2??? I would stop if so as adding the metals to your pool can only cause problems in the future ...

    Still seems like a mystery to me regarding the CYA levels
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: CYA/FC chart making me nervous

    Yes, pool store. I just ordered the TF-100. I will test his and mine back to back when it comes if he doesn't mind. We decided to just maintain the chlorine with the bleach through the week to get us through next weekend and then we are going to drain 50% of the water and convert to salt. Leaning towards the AutoPilot AG from SaltPoolGuys.com. This all seems like a pain but it will be very nice to do everything myself and not have to rely on "the local pool store". Thanks again for all the insight
    10,400 gallon/above ground pool/sand filter

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    Re: CYA/FC chart making me nervous

    The suggested CYA levels for pools with SWG's is somewhat higher than for pools being manually chlorinated, so if your going that route, you will not have to change out as much water.

    Ike
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

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