Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: Combined chlorine

  1. Back To Top    #1

    Combined chlorine

    I have a 17,000 gallon hydrazzo pool with ultra pure auto uv water cleaner.
    My water analysis:
    Ta 150, ph 7.8, cya 45, calcium hardness 400, FC .5, Tc 1, combined chlorine .5. My pool place advised me to get rid of the CC by adding 3 lbs. of shock. Then correct my ph and TA after. I added the shock last night and now my FC is .5+, TC is between 1-1.5. It appears that its slightly gone up. How long after adding shock before I get accurate chlorine readings? Can I fix my TA and PH now or do I need to wait. This pool stuff is new to me and while I'm learning a lot, I have a long way to go.
    IG, 17,000 Gal Hydrazzo; Hayward Filter: S244T 24" Sand; Pump: Sta Rite P6EA6E 1hp 110/220v; Ultra Pure auto UV Water Cleaner
    Built 2011, Taylor Complete Test Kit. Heater: Pentair 300 NT 300,000 Gas; Cleaner: Legend LL505G W/Hayward booster pump; Cover Pools Save T-3 Auto Cover;

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: Combined chlorine

    You can go ahead and adjust your PH & TA if you want.

    For the most part (salt and CYA are longer), you should allow an hour with the pump running after a chemical addition before retesting.

    Any time CC is above 0.5, you should maintain the FC level at shock level (around 16 for your CYA level) until the CC level drops back down to 0.5. This is easier to do with a test kit that includes a FAS-DPD chlorine test (such as the TF100).

    If your FC level 5+, or 0.5+? If it is 0.5+ you aren't using anywhere near enough chlorine. You need to shock the pool, see the instructions in Pool School for the correct way to do that.
    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

  3. Back To Top    #3

    Re: Combined chlorine

    Since i have the Ultra violet water cleaner, I was advised to keep FC at .5 to 1.5. Could this be the case?
    IG, 17,000 Gal Hydrazzo; Hayward Filter: S244T 24" Sand; Pump: Sta Rite P6EA6E 1hp 110/220v; Ultra Pure auto UV Water Cleaner
    Built 2011, Taylor Complete Test Kit. Heater: Pentair 300 NT 300,000 Gas; Cleaner: Legend LL505G W/Hayward booster pump; Cover Pools Save T-3 Auto Cover;

  4. Back To Top    #4
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Combined chlorine

    Welcome to TFP!!!

    That FC is too low based on your CYA of 45ppm to keep the pool clear ... the UV may help some.

    You need to follow the shock process to decontaminate the pool:
    pool-school/shocking_your_pool

    Read the rest of Pool School to get a better understanding of the chemistry while you are at it
    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!

  5. Back To Top    #5
    dmanb2b's Avatar
    Join Date
    Apr 2009
    Location
    NY
    Posts
    3,728

    Re: Combined chlorine

    Is this an indoor or outdoor pool? Either way, with CYA at 45, an FC level of .5-1.5 is too low. UV systems have their place in indoor pools, but not required in outdoor pools.
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

    Pool School, TFTestKits, Pool Calculator

  6. Back To Top    #6

    Re: Combined chlorine

    This is an outdoor pool and my water is crystal clear. What should I get my FC up to? I really appreciate the input. thanks!
    IG, 17,000 Gal Hydrazzo; Hayward Filter: S244T 24" Sand; Pump: Sta Rite P6EA6E 1hp 110/220v; Ultra Pure auto UV Water Cleaner
    Built 2011, Taylor Complete Test Kit. Heater: Pentair 300 NT 300,000 Gas; Cleaner: Legend LL505G W/Hayward booster pump; Cover Pools Save T-3 Auto Cover;

  7. Back To Top    #7
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Combined chlorine

    Read Pool School and your will have your answers:
    pool-school/recommended_levels
    pool-school/chlorine_cya_chart_shock

    You should never let the FC below 3-4ppm. But to go through the shock process you need to maintain a FC of 18ppm.
    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!

  8. Back To Top    #8

    Re: Combined chlorine

    I really appreciate the help! Thanks!
    IG, 17,000 Gal Hydrazzo; Hayward Filter: S244T 24" Sand; Pump: Sta Rite P6EA6E 1hp 110/220v; Ultra Pure auto UV Water Cleaner
    Built 2011, Taylor Complete Test Kit. Heater: Pentair 300 NT 300,000 Gas; Cleaner: Legend LL505G W/Hayward booster pump; Cover Pools Save T-3 Auto Cover;

Posting Permissions

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