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Thread: Cloudy pool - high CYA

  1. Back To Top    #1

    Join Date
    Apr 2009
    Central Minnesota

    Cloudy pool - high CYA

    I am having problems opening my pool (had problems last year as well). 17K gal pool.

    Last year when opening the pool was green and I needed a whopping 70 lbs dichlor before the FC would stay at 10 for any length of time. Needless to say, it took forever because I wasn't adding enough dichlor each time.

    So this year I opened the pool on May 2nd and I thought I would hit it hard right from the get go. But I think I over did the initial chlorination using dichlor. I put in 30 lbs dichlor all in one initial dose. Needless to say, the chlorine test was "bright orange". pH was way low, just like last year. So I added 19 lbs baking soda and 7 boxes borax and the pH came up to 6.8.

    I have not added anything to the pool since May 2nd. I keep the winter safety cover on the pool, so it receives no light. Circulatory pump has been running continuously since then. Water temp is at 58 deg F. Every few days I tested the chlorine and pH levels with a 3 way test kit. The chlorine has very slowly dropped and the pH has very slowly risen over these 17 days. So today (May 19th) I decided to read through these forums closer. I picked up a 6 way test kit at Walmart today to get more numbers.

    Here is what I currently have:
    Total Chlorine 4
    pH 7.3
    Total Alkalinity 200
    Hardness 0
    CYA 110

    Obviously the CYA is way high. I have to think it came from the dichlor I added. Will the CYA level drop slowly over time on its own, or am I stuck with having to drain 1/2 of the pool water?

    Very odd is that my Hardness is 0! Not exactly sure how this can be. I did the test twice thinking the test kit was wrong. I tested my city water with the kit, and its hardness is 100. So is my pool water hardness at 0 because over the past several years, most of the water has come primarily from rainwater and snow melt? Is this a problem?

    The water cloudy/milky. How can I clear this up? Add more chlorine? Or do I need to drain 1/2 the pool?
    18' X 36' X 4.5' vinyl oval in-ground 17K gallons, 250K BTU Pentair Master Temp NG heater, 1HP Hayward Super Pump, Hayward S200 sand filter, Hayward Pool Vac, Extreme mesh safety cover, TF-100 test kit.

  2. Back To Top    #2
    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Houston, Texas

    Re: Cloudy pool - high CYA

    Calcium is not as critical in a vinyl lined pool, you may need to add a little bit but should wait and see if any of the experts suggests adding it to your water. Take a sample to the local pool store and see if they get the same result for calcium. If you have used dichlore on a regular basis if is likely that your CYA is higher than 110. Try diluting the sample by using 1/2 pool water and 1/2 tap water and running the CYA test again. Multiply the results times 2. The only way to reduce CYA is to drain and replace water. If you decide to drain and replace water do it before adding any more chemicals to your water. You need to switch to liquid chlorine to prevent your CYA from getting too high again.
    TFP Moderator
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    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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  3. Back To Top    #3
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Cloudy pool - high CYA

    You need to get your CYA level down to something more reasonable. It will come down slowly over time if you stop using dichlor and trichlor, but that won't be soon enough to help you solve the current problem. Clearing up the pool is going to extremely difficult until you get CYA down to the 50 to 60 range.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  4. Back To Top    #4

    Join Date
    May 2009
    Jasper, TN

    Re: Cloudy pool - high CYA

    Quote Originally Posted by alben
    I needed a whopping 70 lbs dichlor before the FC would stay at 10 for any length of time.

    I picked up a 6 way test kit at Walmart today to get more numbers.
    You're a lifetime supporter but still using dichlor?

    It would have been a lot cheaper to use bleach. As mentioned the dichlor has raised your CYA and you'll have to do a partial drain and refill.

    Also since you're a lifetime supporter, you get a discount at tftest kits... must better testing than walmart's kit especially for FC and CC
    24' x 52" AGP = 13.5k gallons
    Dynamo 2.0 HP pump,Sand Dollar sand filter
    Polaris 65 vacuum (good when there are a ton of leaves on bottom), Pool Rover Jr. (LOVE it, but power box dead right now), AquaCritter (an excellent suction side cleaner)

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