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Thread: Persistently High CYA... Despite Big Rain and Drain

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    Persistently High CYA... Despite Big Rain and Drain

    Relatively new pool owner / TFP follower here. Not knowing any better, used trichlor tabs for about 1.5 years here.
    Stopped tabs on August 8, and switched to liquid chlorine.
    Prior to yesterday, got two consistent readings of 104 for CYA after doing conservative water replacements.
    Yesterday had big rains (remnants of Erika storm). During the storm, I dumped approximately 2000 gallons.
    This morning pH was 7.8 (previously 7.5), FC was 4 (previously 9)... but CYA was still 104... after performing the test twice (dilution method)... what???
    Any thoughts / recommendations would be sincerely appreciated. Thank you.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Mod Squad jblizzle's Avatar
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    Re: Persistently High CYA... Despite Big Rain and Drain

    How are you testing? The recommended CYA test will not give a value of 104.

    It is only logical that your CYA must have been much higher than you think.
    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: Persistently High CYA... Despite Big Rain and Drain

    Hi, JB.
    Used equal amounts of pool water and tap water. Multiplied the reading (around 52 on the comparator) by 2, to arrive at 104.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Re: Persistently High CYA... Despite Big Rain and Drain

    CYA test results should be rounded to nearest 10 ppm.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Persistently High CYA... Despite Big Rain and Drain

    We got a lot of rain on the other coast as well. I bought more CYA because I was low before Erika flooded us. Good luck.
    Pool, 11000 Gallon Gunite Pool, shallow ( < 5' deep ) including spa. Hayward 1750 Cartridge Filter. Pump is a single speed 2 HP Hayward Northstar. Polaris Caretaker 5 Zone Floor System. Pool ~ 8 years old. TF-100 Test Kit.

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    Re: Persistently High CYA... Despite Big Rain and Drain

    OK... CYA is then approximately 100.
    Curious why there was no change in value after a huge storm, and my draining 2K gallons.
    Thank you in advance.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Re: Persistently High CYA... Despite Big Rain and Drain

    The CYA test isn't the easiest to read/gauge, IMO. At at really high levels and really low levels, numbers can be off quite a bit.

    You drained off water that was mixing while it was storming. In other words, you didn't drain 2k gallons first...then filled it up. You drained 2k gallons WHILE filling it up (rain).

    That will lead to much less CYA coming out of your pool than the approximately 30% you might be thinking from draining 2k gallons. (2/7 = 0.29)
    ----Chris----
    25k IG/Spa Figure 8, 18x36, Pebble Sheen Blue Granite, Sta-Rite S8M150 Cartridge Filter, Pentair 460805 400k BTU Heater & 011018 IntelliFlo VarSpd
    Liquidator, Fafco Solar Heat, Polaris PB460 Booster Pump w/280 cleaner, Katchaleaf Cover, TF100 Test Kit, FAKE MAIN DRAIN

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    Re: Persistently High CYA... Despite Big Rain and Drain

    It's correct that I drained while it was raining, Chris. (Really wanted to do the dump earlier, but we were visiting a sick family member.)
    However, when I shut off the submersible, the water level was at the bottom of the skimmer. Over night, the rain brought it up almost 2.5 inches.
    So I was pretty surprised with today's CYA number.
    More rain is expected this week, so I'll likely continue the quest to a CYA below 80.
    Thank you for jumping in.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Re: Persistently High CYA... Despite Big Rain and Drain

    Replaced another 3.5 inches of water last night.
    CYA was 120 this morning. It was at 100 yesterday morning.
    Is the explanation that the CYA test just isn't accurate above 100?
    Any other thoughts?
    Thank you.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Mod Squad jblizzle's Avatar
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    Re: Persistently High CYA... Despite Big Rain and Drain

    Well, it only goes up to 100. Once you start diluting, then the error is multiplied too.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Re: Persistently High CYA... Despite Big Rain and Drain

    For clarification, both tests were done using equal parts of pool and tap water.
    Was surprised with the increase in CYA, since none has been used for almost a month.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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    Mod Squad jblizzle's Avatar
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    Re: Persistently High CYA... Despite Big Rain and Drain

    It did not go up. It is in the noise of the test. Lighting plays a large role in the CYA test. Are you pouring the sample back and forth a few times to see if your readings are consistent?
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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    Re: Persistently High CYA... Despite Big Rain and Drain

    Yup, Jason. Ran the test twice this morning... with identical results.
    Just got back from testing the neighbor's pool. His CYA was 60.
    /L

    7,000 gallon, IG, concrete aggregate pool, Hayward single-speed pump (SP2807X10) w US Motors electric 1 HP / 3450 rpm motor, Hayward Star Clear Plus filter (C751) w cartridge (CX760RE), Taylor K-2006 test kit, SW FL.

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