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Thread: Where did the CYA go?

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    Where did the CYA go?

    Moved post to create your own thread. Always start your own thread rather than hijack another member's thread. Butterfly

    Not sure if this should be a new topic, but my situation does seem similar.

    This is my first year opening the pool (new last year). I'm not ready to open yet, but I did pull off a corner of the cover to get a look and try to get some chemical readings. Water seemed to be slightly green, but I could still see the bottom easily. Unfortunately, my cover does not fit tightly and I do have a bunch of leaves on the bottom. My biggest concern is my CYA level. I opened my brand new TFTestKit and followed the instructions to retrieve a sample of water. I placed the sample on the kitchen counter, so it would warm up before adding the reagent. I added the reagent, mixed, waited, shook and then poured into the view tube. I poured the entire container into the tube and could still see the dot clearly. Last year, the PB started it up and came back out a few weeks later for follow-up. I asked about the CYA level. He checked, thought it was somewhat low and added some stabilizer. Based on what he said, I figured the new level should be between 60 and 80. I did not purchase a CYA test kit last year, but, following directions from here, the pool was clear the entire summer without any issues.

    As stated, my biggest question is my CYA level. I thought that CYA never disappeared (without draining and refilling). I did have to drain the pool twice over the winter, due to rains, but that would not amount to more than 5% of the volume. Does it make sense that CYA would test at 0? If so, where did it go?

    I also tested the pH and Cl levels at > 8.2 and about 1.0 respectively. I'm not going to worry about the pH until I get the pool open and operational. I just want to ensure the Cl levels are high enough that I won't open to a green swamp.
    New (2011) 25000 gal gunite; 21x38; 3.5 - 8' deep; All Hayward: VSP, 48 sq ft DE filter, SWG, 400K BTU Gas heater, PS-8 Controller; Polaris 280

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    Butterfly's Avatar
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    Re: Where did the CYA go?

    Does it make sense that CYA would test at 0? If so, where did it go?
    CYA is sometimes lost over the winter. It is believed that this is caused by anaerobic soil bacteria that can sometimes grow in pool water when the pool is covered and FC levels are zero.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
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    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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    Re: Where did the CYA go?

    Having your pH that high is not good. As soon as you uncover and circulate the pool water, lower your pH. Then add chlorine and start the shcok process. You can shock the pool with 0 CYA or, I would suggest bringing it up to about 20-30 during the shock and then raising it the rest of the way when your pool is clear.
    Dave S.
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    Re: Where did the CYA go?

    My CYA is always near 0ppm when I open.
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    Where did the CYA go?

    This explains why my cya is so low, I expected it to be very high from using pucks but was shocked when I tested it this week to find the test come back less than 30
    The last 2 summers I have been battling cloudy water/algae especially towards the end of season and am convinced it was high cya from the pucks.
    18' x 33' Aqua leader AGP (~19k gal) w/hayward swimpro voyager cartridge filter and 2hp hayward pump.
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    Re: Where did the CYA go?

    Mine is always Zero for the past 2 years when I openened also. Nothing a few weeks of pucks don't solve. Then back to chlorine and/or SWG.
    18 x 36 Inground Gunnite, White Plaster 21K gallon
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    Re: Where did the CYA go?

    Thanks for all the replies. With the high pH, I'll probably open sooner than I had planned, so I can get that under control. With the other responses about 0 or low CYA, maybe I'll throw in a floater with pucks instead of straight bleach to keep it clear.
    New (2011) 25000 gal gunite; 21x38; 3.5 - 8' deep; All Hayward: VSP, 48 sq ft DE filter, SWG, 400K BTU Gas heater, PS-8 Controller; Polaris 280

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    Re: Where did the CYA go?

    Quote Originally Posted by PoolFun
    Thanks for all the replies. With the high pH, I'll probably open sooner than I had planned, so I can get that under control. With the other responses about 0 or low CYA, maybe I'll throw in a floater with pucks instead of straight bleach to keep it clear.
    +1 on the open early & take care of the pH.

    Also, the floater is a good idea because your pool is less than a year old (I think) and the pH rise will still be troublesome. Since the trichlor is acidic, it will help slow the pH rise. Just make sure it doesn't sit in one place.

    Keep a log of how many pucks you add so you can compute/manage the CYA level.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

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    Re: Where did the CYA go?

    Quote Originally Posted by Butterfly
    +1 on the open early & take care of the pH.

    Also, the floater is a good idea because your pool is less than a year old (I think) and the pH rise will still be troublesome. Since the trichlor is acidic, it will help slow the pH rise. Just make sure it doesn't sit in one place.

    Keep a log of how many pucks you add so you can compute/manage the CYA level.
    Not sure I can do much about the floater moving, with the cover still on the pool .

    How can I calculate the amount of CYA added per puck? I've looked through Pool School and some other posts and have seen some references such as 3ppm/puck, but it didn't mention the size of the puck. Is there a reference chart on the forum that may indicate 1" puck = x ppm or y ppm per pound of Tri-Chlor?

    Thanks for all the info.
    New (2011) 25000 gal gunite; 21x38; 3.5 - 8' deep; All Hayward: VSP, 48 sq ft DE filter, SWG, 400K BTU Gas heater, PS-8 Controller; Polaris 280

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    Re: Where did the CYA go?

    use the pool calculator down at the bottom.
    Dave S.
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    Re: Where did the CYA go?

    Quote Originally Posted by duraleigh
    use the pool calculator down at the bottom.
    I have. The calculator tells me to use 267 oz (by weight) of stabilizer. I'm assuming that is for straight stabilizer/conditioner. The piece I'm missing is what percentage of a tri-chlor puck is stabilizer? i.e. if I use 15 lbs of pucks, I'll get 6, 8, 12? lbs of stabilizer.
    New (2011) 25000 gal gunite; 21x38; 3.5 - 8' deep; All Hayward: VSP, 48 sq ft DE filter, SWG, 400K BTU Gas heater, PS-8 Controller; Polaris 280

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    Re: Where did the CYA go?

    duraleigh was referring to the section at the bottom of the poolcalculator labeled: "Effects of adding chemicals"

    In the drop down you can choose trichlor and it will tell you how much cya you will add for a given amount of trichlor added.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Where did the CYA go?

    Thanks Linen. I had not noticed that part of the calculator before. I should be in good shape now. Yes, when I read Duraleigh's comment, I read 'the bottom' as referring to his signature, not the bottom of the calculator!
    New (2011) 25000 gal gunite; 21x38; 3.5 - 8' deep; All Hayward: VSP, 48 sq ft DE filter, SWG, 400K BTU Gas heater, PS-8 Controller; Polaris 280

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