Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 20 of 20

Thread: CH Drop

  1. Back To Top    #1

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    CH Drop

    I measured today and my calcium hardness was 250. I measured twice just to make sure. It had been around 350. What would cause such a drop? Poolmath says I need to add about 25lbs to get it back into range.



  2. Back To Top    #2

    In the Industry

    bdavis466's Avatar
    Join Date
    Aug 2014
    Location
    Riverside, CA
    Posts
    3,309

    Re: CH Drop

    Rain or a leak. Really the only two ways the CH could have lowered on its own.

    Have you had either?
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

  3. Back To Top    #3
    Casey's Avatar
    Join Date
    Apr 2007
    Location
    SW PA
    Posts
    10,157

    Re: CH Drop

    Yes, adding water is about the only way it could lower.
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

  4. Back To Top    #4

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    Yea forgot about that. We did have a heavy rain Saturday night.


    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  5. Back To Top    #5
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,499

    Re: CH Drop

    A heavy rain wouldn't do it. You would have to replace almost 1/3 of the water in the pool to have that kind of drop.
    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
    Aug 2014
    Location
    Northern IL
    Posts
    4,615

    Re: CH Drop

    You have a new pool with significant potential issues from the "cloud" the PB created. I think the CH issue may be related. Would you please post this same question on one of your more active previous threads? This thread may be your best option due to the quality of the followers:
    Mottling

    It is important for us to know your history as you are in the process of dealing with major! issues.

  7. Back To Top    #7

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    The CH has been normal since the beginning. We had a heavy rain since my last normal test. The chemicals have been testing normal. I'm not sure why my post about the original start up is referenced or would have bearing to CH drop after a significant rainfall.


    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  8. Back To Top    #8
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,499

    Re: CH Drop

    Quote Originally Posted by Shock11 View Post
    CH drop after a significant rainfall
    could the rainfall have displaced over 6,000 gallons of water? It would have had to have spilled over the coping or was pumped out. Did either of those occur?
    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

  9. Back To Top    #9

    Join Date
    Aug 2014
    Location
    Northern IL
    Posts
    4,615

    Re: CH Drop

    Quote Originally Posted by Shock11 View Post
    ...I'm not sure why my post about the original start up is referenced...
    I have just been concerned about your start-up ever since the cloud appeared upon filling. I felt that your history might be important. Good luck with everything!

  10. Back To Top    #10

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,085

    Re: CH Drop

    I measured today and my calcium hardness was 250. I measured twice just to make sure. It had been around 350. What would cause such a drop? Poolmath says I need to add about 25lbs to get it back into range.
    To get back into what range? What does Pool School say about acceptable range for CH.

    CH does not drop on it's own. Rainfall won't change it that much. What's left? Testing error is the only thing I can conceive.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  11. Back To Top    #11

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    Quote Originally Posted by tim5055 View Post
    could the rainfall have displaced over 6,000 gallons of water? It would have had to have spilled over the coping or was pumped out. Did either of those occur?
    It did get drained out through the overflow and into the yard. I seriously doubt I lost 6000 gallons.


    Sent from my iPhone using Tapatalk

    - - - Updated - - -

    Quote Originally Posted by duraleigh View Post
    To get back into what range? What does Pool School say about acceptable range for CH.

    CH does not drop on it's own. Rainfall won't change it that much. What's left? Testing error is the only thing I can conceive.
    Well I test anything that is not in normal range twice to make sure that it is tested correctly. The only difference is that I used the speed stir. So the only error would be that the speed stir causes a difference in reading due to the amount the solution is mixed.
    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  12. Back To Top    #12
    Mod Squad tim5055's Avatar
    Join Date
    May 2014
    Location
    Columbia, SC
    Posts
    8,499

    Re: CH Drop

    Quote Originally Posted by Shock11 View Post
    The only difference is that I used the speed stir. So the only error would be that the speed stir causes a difference in reading due to the amount the solution is mixed.
    If you are saying you hand stirred for the 350 result and the speedstir for the 250 result then you have your answer. It is very common for this to drop when changing from hand stirring to usin a speedstir.
    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

  13. Back To Top    #13

    Join Date
    Oct 2015
    Location
    Katy/Texas
    Posts
    411

    Re: CH Drop

    Test results will be more accurate, consistent or repeatable using the speedstir.
    In ground, 14,000 gallon, white plaster, unheated, stone waterfall, DE Filter, Rainbow 320 Cl, Polaris 3900, FloVis flow meter, F100 test kit, Circupool RJ30+ SWG, Circupool VJ1/Speck Badu EcoM3V variable speed pump.

  14. Back To Top    #14

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    I'm going to pick up some calcium chloride. Being that the pool has been filled for a month, should I raise to 350 or just raise slightly since it's currently 250? They haven't put the salt in yet so I'm still treating it as a bleach pool. Being that the water is 52 degrees, should I dilute in a bucket first or broadcast?
    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  15. Back To Top    #15

    In the Industry

    bdavis466's Avatar
    Join Date
    Aug 2014
    Location
    Riverside, CA
    Posts
    3,309

    Re: CH Drop

    You need to post a full set of numbers. There are a lot of other factors that come into play and have a direct effect based on the CH level.
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

  16. Back To Top    #16

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    PH: 7.8
    FC: 3
    TA: 60
    CC: .5
    CH: 250
    CYA: not measured


    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  17. Back To Top    #17

    In the Industry

    bdavis466's Avatar
    Join Date
    Aug 2014
    Location
    Riverside, CA
    Posts
    3,309

    Re: CH Drop

    Your numbers are fine where they are now since they yield a CSI of -0.26.

    The decision to add calcium is going to based on the CH of your fill water, the rate of evaporation you expect to experience, and the average annual rainfall. I my area, with so little rain, we constantly fight rising calcium levels so adding calcium would only make the problem worse and require a water replacement sooner than if no calcium was added.

    Once you add salt to the pool, your CSI will drop further to -0.49 (assuming 3200 ppm and your current numbers). It would be best for you to target a pH of 7.6-7.8 and maintain the TA around 60-70.

    Use Pool Math to calculate The CSI for you. Shoot for +0.1 to -0.2
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

  18. Back To Top    #18
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: CH Drop

    You do not need to add Calcium to your pool. Be grateful it is where it is. It will come up in time on its own.
    TFP Moderator
    Essential Links:
    ABC's Of Pool Chemistry, Test Kits, SLAM Your Pool
    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

  19. Back To Top    #19

    Join Date
    Oct 2015
    Location
    Burleson, Texas
    Posts
    178

    Re: CH Drop

    Quote Originally Posted by Patrick_B View Post
    You do not need to add Calcium to your pool. Be grateful it is where it is. It will come up in time on its own.
    I thought it was the opposite. I thought that you would not want your CH to be low and pull calcium from the new plaster.
    21,000 gallons, Salt, IG Gunite, Plaster Finish, Free From, Pentair FNS DE cartridge filter, Pentair Intelliflo-VS pump, Intellichlor IC-40, 2 port fountains, bubbler in tanning deck, Dolphin M400, TF-100, K-1766, Speed Stir

  20. Back To Top    #20

    In the Industry

    bdavis466's Avatar
    Join Date
    Aug 2014
    Location
    Riverside, CA
    Posts
    3,309

    Re: CH Drop

    Other factors play into the aggressiveness of the water, thats what the CSI is for. The actual calcium content in the water has surprisingly little to do with it.

    PH has the biggest effect, so keeping the pH on the higher side of things will help (in addition to requiring less acid to maintain), TA has the next biggest impact. Play with some numbers in pool math and see how the CSI changes.

    Plaster degradation occurs around -0.7 (which you are well above), and even then, its a slow process.

    Your calcium level is fine where it is now. The recommended levels are nothing more than a guideline to simplify things for those that don't use the CSI.
    -Brian-
    33K Pool/Spa, Pentair Equipment
    POOL BUILD
    Davis Custom Construction - Home Page

Posting Permissions

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