Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 14 of 14

Thread: Free chlorine drops so quickly in crystal clear pool with all other levels good!?!

  1. Back To Top    #1

    Join Date
    Jul 2014
    Location
    Mesa, Arizona
    Posts
    5

    Free chlorine drops so quickly in crystal clear pool with all other levels good!?!

    Hi all,

    Firstly, my apologies for posting another message about chlorine levels. I have spent quite some time reading through prior posts, but none quite match my situation.

    I have a 12000 gallon pool with a hayward sand filter. We drained and refilled the water recently. I have finally got the CYA levels up to 40-50 last week. The acidity is a little high last I checked, but nothing serious and all other levels are where they should be, and they stay pretty consistent. The water has been crystal clear and wonderful.

    My problem, however, is that I cannot maintain free chlorine levels. I added enough 8.25% bleach last night, for example, to raise the fc levels to around 7. This morning the FC was about 6, which I thought was fine. Now, late afternoon and the FC is zero! It's been like this for the past two weeks and the grocer at the supermarket is starting to eye me suspiciously because I am buying liquid bleach so frequently!

    Seriously though, apart from our excessive 100+ heat here in Phoenix, I do not know why I am loosing FC so quickly and I am very frustrated and I would apprecate some advice. My CYA levels are fine so I don't think that is the problem and I haven't seen any cloudiness or discoloration at all that would suggest organics eating the chlorine. the water is so clear, but I am so frustrated!


    Here are my current specs (late afternoon):

    Fc - 0
    Ph 8.0
    TA - 170
    CH 230
    Kit: taylor k2006 fas-dpd

    Thanks up front for any suggestions!

    E

  2. Back To Top    #2

    Join Date
    Jul 2012
    Location
    Herndon, VA
    Posts
    419

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    What exactly is the CYA level? "Fine" does nothing to help diagnose what to do.
    8,000 gallon, in ground, fiberglass pool with a cartridge filter.

  3. Back To Top    #3

    Join Date
    May 2013
    Location
    North East Ohio
    Posts
    953

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Quote Originally Posted by GuinnessPhish View Post
    What exactly is the CYA level? "Fine" does nothing to help diagnose what to do.
    I think he said 40-50, in the thread...

    Just a comment, my pool has been eating CYA as well - will be watching this to see if there is a solution, have no advice.
    14,750 GAL IG Fiberglass (16 x 33) NE Ohio || Jandy 1HP 2 speed Pump || Waterco MultiCyclone 16 Centrifugal pre-filter (removed due to not working with sand filter) || 30" 575 Lb. Sand Filter || AquaCal 140K BTU Heat Pump || Solar Cover || Inter-fab Adrenaline Slide || GLI Monsoon Solar Cover Reel || K-2006C Test Kit || BBB with Liquid Chlorine Stenner Injection || Rayner Mighty Mesh Winter Cover

  4. Back To Top    #4
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,089

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Chlorine consumption during the day with little loss overnight points to low CYA. Take a look at http://www.troublefreepool.com/threa...l=1#post203524 to verify your results.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  5. Back To Top    #5
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,495

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    It would help us if you would add the following information to your signature

    • The size of your pool in gallons
    • If your pool is an AG (above ground) or IG (in ground)
    • If it's IG, tell us if it's vinyl, plaster/pebble, or fiberglass
    • The type of filter you have (sand, DE, cartridge) and, if you know, the brand and model of the filter.
    • If you know, please tell us the brand and model of the pump, and mention if is it a two speed or variable speed pump.
    • Date of pool build/install, particularly important if less then a year old.
    • What kind/model of water test kit you are using
    • Other significant accessories or options, such as a spa , SWG, or cleaner
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

  6. Back To Top    #6

    Join Date
    Jul 2014
    Location
    Mesa, Arizona
    Posts
    5

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Hi all,

    Thanks for the replies. I bumped the chlorine levels up to 16 last night, testing the levels after about two hours of circulating the water. This morning the FC was down to around 10. Ugh. 6 ppm drop overnight just does not seem right. The pool is crstal clear like usual. I imagine that by this afternoon the FC levels will be back to 0. I am spending so much money on bleach...

    I have a 12k gallon in ground pool with pebble tech lining.
    We have a Hayward sand filter, model s244sv with an intelliflow variable speed vs3050 pump.
    The pump runs from 3 pm to midnight, if the timing makes a difference in this situation.
    The pool came with house (we moved in a year ago) so I do not know exactly how old it is.
    No other accessories.

  7. Back To Top    #7
    MBG75's Avatar
    Join Date
    Jun 2013
    Location
    Long Island
    Posts
    184

    Free chlorine drops so quickly in crystal clear pool with all other levels go...

    If you lost 6ppm overnight. You need to SLAM the pool

    Only algae and sunlight eat chlorine.
    25k IG vinyl SWG Haywood 4830de 1.5hp TF-100

  8. Back To Top    #8

    Join Date
    May 2014
    Location
    Oro Valley, AZ
    Posts
    120

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Quote Originally Posted by azpoolguy16 View Post
    I added enough 8.25% bleach last night, for example, to raise the fc levels to around 7. This morning the FC was about 6, which I thought was fine. Now, late afternoon and the FC is zero!
    This part of your first post sure sounds like a failure of the OCLT and means you really need to do the SLAM process. You lost 1ppm overnight and then a significant amount during the day which indicates you have organics eating up some of your FC. You may feel you are putting in a lot of bleach but if you don't keep it up at SLAM levels you're feeding it just enough to stay alive.

    First I would get your pH down to 7.2 to 7.4 and then dose with bleach to SLAM levels and keep it there till you pass the overnight test. It sounds like you dosed it up to SLAM level and then let it drop back to zero. You're in AZ like me so maybe your pH rises constantly like mine does. Once you finish the SLAM you're gonna probably want to keep bringing the pH down with MA and then let it naturally rise back up and eventually your TA level should lower.

    Regarding CYA level I'm not buying the theories I'm hearing about FC eating up CYA. If that's really a problem I'll be glad to sell someone half my pool water and I guarantee my CYA is robust. I haven't seen my number budge in the negative direction in two months even after weekly backwashing. My CYA was over 100 and I replaced half my water a couple months ago and I've been running steady at CYA = 65. If someone has a pool eating CYA then they can just float trichlor pucks and be done with all the headaches.

    My only other suggestion is maybe try running your pump from 8am to 5pm like I do. I know your probably trying to save electricity but during the day is when algae comes out to bathe in the sun and I really think a pool needs the water circulating for a good portion of the day when you live in a hot area like we do.
    Thanks,
    Gil

    In-ground: 20,600 gallons; Sand Filter 1HP pump; Kreepy Krauler; Solar Breeze Solar Powered Robotic Skimmer; TFT-100 test kit

  9. Back To Top    #9

    Join Date
    Jul 2014
    Location
    Mesa, Arizona
    Posts
    5

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Wow, thanks for the quick replies; just another reason why I switched to the TFP system. OK, I am researching the SLAM process now and will return when I have more info.

    In the meantime, does algae and organics live only in the water or can organic material trapped in the sand filter act as an incubator? I replaced the sand last year and backwash routinely, but we had several weeks where a ton of debris fell into the pool though it never went green or cloudy. I'm just trying to work through everything I need to do (SLAM) or could do (replace sand?) to fix this issue asap.

    Cheers.

    Erich

  10. Back To Top    #10
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,495

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Quote Originally Posted by azpoolguy16 View Post
    Wow, thanks for the quick replies; just another reason why I switched to the TFP system. OK, I am researching the SLAM process now and will return when I have more info.

    In the meantime, does algae and organics live only in the water or can organic material trapped in the sand filter act as an incubator? I replaced the sand last year and backwash routinely, but we had several weeks where a ton of debris fell into the pool though it never went green or cloudy. I'm just trying to work through everything I need to do (SLAM) or could do (replace sand?) to fix this issue asap.

    Cheers.

    Erich
    I wouldn't replace sand, a Deep Cleaning if anything. Yes, organics can live anywhere your pool gets wet and stays wet. In ladders and behind lights is the most common area as they stay wet but have poor circulation to bring fresh chlorine into the area.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

  11. Back To Top    #11

    Join Date
    Jul 2014
    Location
    Mesa, Arizona
    Posts
    5

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Hi all,

    Just a quick update for those following this thread. Chlorine levels dropped slowly yesterday after I began to SLAM the pool in the morning. We only lost about 4 ppm between 6 am and 3 pm (from 16 to 12 ppm FC), but interestingly the FC was significantly lower by 6 pm - around 2 ppm. I'm wondering if that's because it is the hottest part of the day? Anyway, yesterday I also did a deep cleaning of our sand filter and backwashed.

    I've also gotten the pH to 7.4, but after several treatments of muriatic acid, I'm finding it difficult to get the pH to 7.2, which will help with the high TA levels (TA 140). I added 20 oz more muriatic acid this morning, following the poolcalculator, and I hope it finally gets the pH to where I want it.

    Lastly, after maintaining chlorine levels yesterday and last night I calculated only a ~2 ppm loss this morning (from 16 ppm to 14 ppm), which is better than before but still does not pass the OCLT. We are continuing to SLAM the pool again today and I will post new results as they come in.

    The pool remains clean and wonderful, but I'll just be happy to get the chlorine loss under control.

    Cheers,

    Erich
    12,000 gallon in ground pool with pebble tech lining. Hayward sand filter, model s244sv with an intelliflow variable speed vs3050 pump.

  12. Back To Top    #12
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Yes, you will lose more FC to the sun in the afternoon. At 3PM did you raise the FC back up to shock level?

    You can not test the pH when the FC>10ppm ... the pH will read artificially high.
    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!

  13. Back To Top    #13

    Join Date
    Jul 2014
    Location
    Mesa, Arizona
    Posts
    5

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Unfortunately, we didn't have chlorine at 3 pm. After we got home with new chlorine at 6 pm then we raised the shock level up again.

    Thanks for the info on the pH and FC levels!
    12,000 gallon in ground pool with pebble tech lining. Hayward sand filter, model s244sv with an intelliflow variable speed vs3050 pump.

  14. Back To Top    #14
    MBG75's Avatar
    Join Date
    Jun 2013
    Location
    Long Island
    Posts
    184

    Re: Free chlorine drops so quickly in crystal clear pool with all other levels good!?

    Pool has to stay above the minimum FC for your CYA.

    keep it at SLAM level till you pass the OCLT.

    ImageUploadedByTapatalk1406133271.519494.jpg
    25k IG vinyl SWG Haywood 4830de 1.5hp TF-100

Posting Permissions

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