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Thread: newbie question on cya and fc

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    newbie question on cya and fc

    using the bbb method and my cya level is at 60 and my fc level is at 6/7 and my questions are as follows

    - does this high fc level damage my pool or the equipment?
    - if I lower my cya level to 30/40 and my fc to 4/5 will the fc burn off faster and require mme to add more bleach thatn I do at the higher cya level?

    - any recommendatin on how to maintain my fc while I am out of town for 7 days, since I won't be able to add bleach? should I revert to the chlorine pucks?
    pool was built in 5/11, in ground 37,000 gallon concrete/plaster pebble sheen finish. STA-RITE system 3 Cartridge filter 400sqft filtration area, .288 gpm/sqft, 115 gpm flow rate. also has a Nature 2 mineral sanitizer and a 1hp sta-rite pump

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    linen's Avatar
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    Re: newbie question on cya and fc

    Quote Originally Posted by jws13
    - does this high fc level damage my pool or the equipment?
    No...if you have a proper level of cya in the water (which you do). The Chlorine/CYA chart values were picked so that the levels would be safe for your pool (and you). When your measure FC, you are measuring both the active "chlorine", which is a pretty low concentration, and the "reserve chlorine" that is being held in reserve by the cya and is much less aggressive and how most of the chlorine exists in the pool. If you want more detail see: http://www.troublefreepool.com/pool-...stry-t628.html

    Quote Originally Posted by jws13
    - if I lower my cya level to 30/40 and my fc to 4/5 will the fc burn off faster and require mme to add more bleach thatn I do at the higher cya level?
    I depends on many factors: amount of sun, temperature, swimmer load, etc. Most people without swg's, have efficient chlorine use around 50 ppm. If I were you, I would go with what you have and see how much chlorine you use daily, next time you drain for winter (or some other reason) shoot for around 50 ppm.

    Quote Originally Posted by jws13
    - any recommendatin on how to maintain my fc while I am out of town for 7 days, since I won't be able to add bleach? should I revert to the chlorine pucks?
    I wouldn't add anymore pucks since you cya is already a little high. Is there anyone who could add chlorine to your pool every couple of days? If not, and because 7 days is a long time, it will be hard to stay above your minimum FC level, but you could try to bring it to shock level before you leave and then hope for the best. If you have a non-transparent cover that will help a lot.
    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: newbie question on cya and fc

    Quote Originally Posted by jws13
    using the bbb method and my cya level is at 60 and my fc level is at 6/7 and my questions are as follows
    - does this high fc level damage my pool or the equipment?
    No, not at that CYA level. You are not even close to shock level.

    - if I lower my cya level to 30/40 and my fc to 4/5 will the fc burn off faster and require mme to add more bleach thatn I do at the higher cya level?
    No, you will add less bleach to get to your correct fc level (and shock level) than at your current cya level, however, you might burn off a higher percentage each day. The recommended amount is generally a cya of 50.

    - any recommendatin on how to maintain my fc while I am out of town for 7 days, since I won't be able to add bleach? should I revert to the chlorine pucks?
    The best case would be for you to have someone add your normal bleach addition each day. Another route would be to take it up to shock level and then have someone come in on day 3 and add a similar amount again. If you don't have any assistance with bleach, then you probably should use the tablets, however, when you return, you might need to do a partial drain/fill because you are already a little high on the cya.
    20k gal, IG Vinyl, IntelliFlo VF Pump, 60 GPM sand filter, Jandy Aquapure Ei 35, 2 skimmers, one main drain, two returns, Dolphin Diagnostic cleaning robot, Taylor K-2006 test kit

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