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Thread: What is a safe level of chlorine to swim at with high CYA levels

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    What is a safe level of chlorine to swim at with high CYA levels

    I am probably supposed to start my own thread, but I had a very similar question about CYA/algae. Moderators please move me if necessary.

    Unfortunately, I was lazy and used the pucks for too long this past spring. I started with a CYA around 50-70 before the pucks. While I was out of town last week I left my hubby in charge and he does not do "pool stuff" well. I told him to put in a gallon of 10% chlorine the day he told me he was beginning to see algae. He put in the bottle of regular bleach instead. It wasn't enough to shock the pool. Anyway, water is now cleared up after two days of 2gallons 12% chlorine.

    My question is, now that my CYA is so high- (best estimate using the test kit is 120-140- CYA is still hard for me to read after a year of doing this) what is a safe level of chlorine to swim at with my high CYA levels? FC=17? I am about out of R-0871. Can I get more at Leslie's? or do I need to order from TFP? I have a 5 year old grandson and I don't want to harm his delicate skin. Any help would be appreciated. Also, my understanding is that I just have to keep a much higher FC level with the high CYA for the chlorine to be effective, correct?

    I did actually drain off about 6 inches of water yesterday and then refilled about 8 inches total. 2 inches was evaporation loss. CYA was still above 100 for sure. I did read that to get my CYA levels down I should drain half of my pool. I have to drain to the street because we are on septic and I'm not sure how kindly the neighbors would take to 5,000 gallons running down the street. How much CYA does each of those darn "pucks" add?

    I converted from Bacquacil last summer and I'm still glad I did.

    CYA 120-140 see above explanation
    pH 7.5
    TA 90
    CC .5 two days ago while shocking pool
    FC- can't test out of reagent, last read before shooking the pool was 14.5 and two days ago while shocking 26.5
    10,000 gallons Splash Pool; cartridge filter; vinyl; AG; pump Sta-Rite 1 HP

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    Re: chlorine usage at different cya levels

    I just found the CYA/chlorine chart in someone else's signature line. I think that is a new chart- I don't remember it from last summer. I think I answered my own question, but any replies would still be appreciated.

    Thanks TFP for your existence!!!
    10,000 gallons Splash Pool; cartridge filter; vinyl; AG; pump Sta-Rite 1 HP

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    Mod Squad Bama Rambler's Avatar
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    Re: chlorine usage at different cya levels

    Since you found the chlorine/CYA chart you have made great headway. You can swim up to the shock level for your CYA level.
    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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    JasonLion's Avatar
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    Re: What is a safe level of chlorine to swim at with high CYA le

    The Pool Calculator is able to calculate the correct FC levels for very high CYA levels, well above where the Chlorine / CYA Chart stops.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Richard320's Avatar
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    Re: What is a safe level of chlorine to swim at with high CYA le

    My CYA is about the same as yours. We had some kids 5 - 8 years old over last Saturday swimming with 16 FC and no complaints.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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    Re: What is a safe level of chlorine to swim at with high CYA le

    Quote Originally Posted by Richard320
    My CYA is about the same as yours. We had some kids 5 - 8 years old over last Saturday swimming with 16 FC and no complaints.
    Richard: Thanks for the info. I feel better now.

    Jason: So the kids can swim up to the shock level? That is like 40 ppm...really? Also, no one answered my question about how much CYA is in one of those 3" pucks.

    I appreciate the TFP site- it has always been much more helpful than the pool store. I don't even go there anymore.
    10,000 gallons Splash Pool; cartridge filter; vinyl; AG; pump Sta-Rite 1 HP

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    Re: What is a safe level of chlorine to swim at with high CYA le

    You can use the Pool Calculator in reverse by typing in FC levels and adjusting the numbers slightly up or down until the output is a weight of 200g trichlor (or the weight of a single puck), then that gives you the answer for your pool. Then multiply the FC by 0.6 to get the CYA adjustment. I worked out for my pool that each puck would raise FC by 2.4 and CYA by 1.4. There might be an easier way to work it out, but this is what I used.
    90k litres, outdoor in ground pool, concrete, painted (I hate paint)
    Sta-Rite 5P2R 1.5 Hp pump, undersized sand filter (needs upgrading).

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    Melt In The Sun's Avatar
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    Re: What is a safe level of chlorine to swim at with high CYA le

    horsegal, how much CYA is in the puck depends on your pool size (10,000 gal) and the puck size (8 oz? 7 oz? Look on the container). Then you can use the pool calculator's "effects of adding chemicals" section to figure it out.

    looppea beat me to it (sorta), but I think using the "effects of adding chemicals" section is easier.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
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    Re: What is a safe level of chlorine to swim at with high CYA le

    Thanks ladies/gents for your responses. I never thought to use the pool calculator to work backwards. I'll give it a try. My pucks are 8 oz. trichlors btw. Today my pool is beautiful sparkly clear since I shocked it with two gallons of 12% a couple of days ago and keep the pump running continuously for two days. My husband wouldn't listen to me when I told him how much chlorine to put in and to let the pump run. He kept shutting it off after 8 hours and letting it sit. Hopefully I will have time to enjoy the pool this week
    10,000 gallons Splash Pool; cartridge filter; vinyl; AG; pump Sta-Rite 1 HP

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