Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 10 of 10

Thread: CYA and FC question

  1. Back To Top    #1
    astronaut888's Avatar
    Join Date
    Jun 2013
    Location
    southeast
    Posts
    118

    CYA and FC question

    Forgive the basic question.

    Presently

    CYA 50 (may be slightly lower)
    TA 100
    pH 7.5
    FC 7 - tested this morning at dawn
    CC 0 - every now and again will turn slightly pink w 003 - but, subsequent tests don't turn - so, could be 0.5
    Water looks beautiful and clear (!)


    Depending on the day's weather, I have been adding anywhere between 30 and 90oz(ish) 8.25% bleach in the evenings [ 30 oz raises FC 1 ]



    With respect to FC levels
    Pool School suggests between 4 and 6 FC for a CYA of 50 - I'm not entirely sure that CYA is 50 and not closer to 40 as I have a **** of a time determining whether or not I can still see that black dot!!
    I've erred on the side of assuming it is higher as to not let FC get too low

    My question is : I know I never want it to go below 4 (ever, right?) - but, raising to only 6 concerns me, as it does get down to 4 on sunny days, which, to me, Is dangerously close to getting TOO low
    So, should I be raising HIGHER than 6 in the evenings? i.e., should I target 7 or 8 with my bleach additions ?


    Also, There hasn't really been any use of he pool this season yet and I have a party coming up this weekend with lots of folks and kids and the pool is going to be rocking
    Would it be advisable to kick the FC up a notch before folks show up - get it to 7 or 8 before experiencing such a bather load?
    I have yet to see how the pool reacts to folks actually USING it (!)

    Thanks!!
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

  2. Back To Top    #2
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,965

    Re: CYA and FC question

    The pool will not turn green if you let the FC get to 3 for a few hours before you add chlorine. LOL I'm gonna tease you a little bit.

    We have a range- a cushion if you will. We stress "ALWAYS" and "NEVER LET IT" because we want people to "get to know their pool" and be diligent - because it's oversight and negligence that leads to problems.

    The avg loss is 2ppm per day. This is an avg. Get to know your pool. Try 7 or 8 and see where you end up. Maybe it will be a more comfortable place for you.

    Yes for a party I'd even go to 10. Test when party is over and bump it back up. That's what I do.

    Have a fun party!
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  3. Back To Top    #3
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: CYA and FC question

    The chart you are using from pool school does round up a bit, with a CYA of 50, the actual minimum you want to stay above is 3.7 ppm, and even that does not mean if you drop below it a little that you will have problems, just that the chances go up. If your CYA number is a little below 50 then that number is likely closer to 3.5 or less for minimum FC. Having said that I agree with the suggested target numbers mentioned by Frustratedpoolmom
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  4. Back To Top    #4
    astronaut888's Avatar
    Join Date
    Jun 2013
    Location
    southeast
    Posts
    118

    Re: CYA and FC question

    Thanks for replies!

    I really don't know what the concern would be in keeping the FC a bit higher, honestly. Not suggesting that there isn't a concern, just that I am unaware of what the concern would be, other than maybe using more product than I really needed - however, If I see that I am losing , say, 2 PPM per day - what would be the difference if this loss was from 6 to 4 OR 8 to 6?
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: CYA and FC question

    If your pool goes from 6 to 4 during a typical day, and you instead started at 8 you would lose more than 2 ppm of chlorine. The amount of chlorine used is a percentage of your starting level.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  6. Back To Top    #6
    astronaut888's Avatar
    Join Date
    Jun 2013
    Location
    southeast
    Posts
    118

    Re: CYA and FC question

    Quote Originally Posted by JasonLion View Post
    If your pool goes from 6 to 4 during a typical day, and you instead started at 8 you would lose more than 2 ppm of chlorine. The amount of chlorine used is a percentage of your starting level.
    so, would be, in fact, a waste of money/bleach essentially?
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

  7. Back To Top    #7
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: CYA and FC question

    Right. It might not be all that large of a waste, but it would be some chorine wasted.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  8. Back To Top    #8
    astronaut888's Avatar
    Join Date
    Jun 2013
    Location
    southeast
    Posts
    118

    Re: CYA and FC question

    pool.jpg

    gonna use this thread to test and see if i am able to properly upload an image
    thanks for entertaining me
    20K gal, IG vinyl, 1 1/2 HP Hayward Super Pump , 100lb sand, installed 2000 - new liner/filter/pump March 2014
    TF-100 test kit

  9. Back To Top    #9
    frustratedpoolmom's Avatar
    Join Date
    May 2007
    Location
    SWSuburban Chicago, IL
    Posts
    11,965

    Re: CYA and FC question

    Keep the raccoon out of the truck, and the POOL! Gorgeous!
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

  10. Back To Top    #10
    smforte's Avatar
    Join Date
    Sep 2013
    Location
    Montgomery,Al
    Posts
    668

    Re: CYA and FC question

    Beautiful pool....I wish I had your liner color! Love that color blue!
    Montgomery, AL
    27000 16 x 36 IG, Vinyl, Grecian, Hayward Sand filter, 1 HP Pentair whisperflo motor, Aqua Genie filter not by choice, no extra jets, Dolphin s300i robotic cleaner,Taylor K 2006 test kit, speed-stir which I couldn't live without!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •