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Thread: higher cya safe?

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    higher cya safe?

    on the chlorine CYA chart the higher the cya the more chlorine it says needs to be reached .. as far as I knew only 2 ppm chlorine is a safe level .. going over 3 and up is hazardous .. what am I not understanding completely .. the efficiency of the chlorine? how can i test that in pool water? I;'ve been hold 5 plus chlorine for the last week .. two people have been in it no problems .. except for a light green pool
    21X41, 30,000, ig, vinyl,48sf de, 1hp hayward super pump, 2" piping, 2 skimmers, 1 main inlet, 2 return, built in 1988, no enclosure, lots of trees around, direct sun. Thanks in advance to all who have answered my questions.

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    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    SouthWest Alabama

    Re: higher cya safe?

    Do a little reading of Chem Geek's posts in the deep end and you'll find your answer. The recommemded levels with CYA is a lot less active chlorine than 2 ppm without anny CYA in the water.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: higher cya safe?

    ....."Light Green" pool is a sure sign you're headed for problems quickly. See shocking your pool in pool school.
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
    Pool Rover Jr., Pool Blaster Max, Diver Dave TF100 Test Kit/Speed Stir
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    Join Date
    Jun 2010
    Glendale, CA

    Re: higher cya safe?

    It comes down to Active chlorine in the water. So FC of 5 with a CYA of 40ppm will have an active chlorine level of 0.04ppm (or something like that - see the chart in the post below). The rest of the Chlorine is bound in the CYA and not active. Chemgeeks post is here


    Also keep in mind the FC guidelines you are referencing are based on EPA drinking water standards and assume 0 CYA in the water. The EPA says you can have 4ppm chlorine in your drinking water - with no CYA. So if your drinking water in a closed pipe can have 4ppm of active chlorine - putting 0.04 ppm active chlorine in the open pond in your backyard can't be that toxic right? ... ctants.cfm

    Sounds like your pool has a pretty high CYA and your FC level of 5 isn't high enough to keep up with the algae. If you post a full set of test results we can help.

    Good luck
    16K Gal Plaster | Compupool SWG | Intelliflow VF | TF-100

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    Join Date
    Mar 2007
    San Rafael, CA USA

    Re: higher cya safe?

    Most of the chlorine is bound to CYA while the standards for pools are based on drinking water standards with no CYA even though you are not drinking quarts of pool water. See this post for limits for commercial/public pools set by states that are higher than the 4 ppm EPA drinking water standard (Florida allows up to 10 ppm).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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