Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: Why does CH drop?

  1. Back To Top    #1
    nolefan's Avatar
    Join Date
    Jun 2011
    Location
    Ft. Lauderdale, FL
    Posts
    19

    Why does CH drop?

    I have been maintaining my own pool using the information on this site since the beginning of June. It has never looked better and I am getting the hang of it. My CH has been holding steady at 300 since i started. But over the last 3 weeks, it has slowly started dropping off. It measured today at 250. Where does it go? Does the pool use it? It has been raining a lot over the last few weeks and I have been dumping the excess water. Did I just answer my own question? Do I need to add more CH to bring it back up as I dump water?

    Thanks for the Help:

    FC: 5.5
    TC: 0.5
    PH: 7.6
    CH: 250
    TA: 70
    CYA: 70
    12,000 gal / IG: Diamond Brite / Pool Pilot Digital SWCG / SC-36 Salt Cell / Hayward 1 hp pump / Pentair CNC 100 / Solar Heater

  2. Back To Top    #2
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: Why does CH drop?

    Quote Originally Posted by nolefan
    It has been raining a lot over the last few weeks and I have been dumping the excess water. Did I just answer my own question?
    Yes, you did. If you've been having to drain water you're also draining CH.

    I would watch it and if it gets much lower than 250 I'd bump it back up to ~300.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  3. Back To Top    #3

    Re: Why does CH drop?

    You are also draining CYA and TA. Should have seen them each decrease by some 1/6th as well.

    (edit for clarity) Since you are having so much rainwater added to the pool, that rain, with 0 CYA and 0 TA ought to be diluting the pool and as you drain off the excess, some of that CYA and TA is leaving, just like the CH has. So, I would be expecting those levels to have changed a bit also, at least to the extent of the accuracy of the CH testing that shows you lost 50 ppm of 300 ppm. That is, if you are using the sample size that has one drop = 25 ppm CH, then your accuracy is less than if the sample used means one drop = 10 ppm CH.

    None of this is critical, just a comment to watch those other numbers as well.

    In winter it is usually wet here and I see all these values go down together.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

  4. Back To Top    #4
    nolefan's Avatar
    Join Date
    Jun 2011
    Location
    Ft. Lauderdale, FL
    Posts
    19

    Re: Why does CH drop?

    You are correct. All those levels have dropped as well. Somehow I didn't correlate it to me dumping the water.
    12,000 gal / IG: Diamond Brite / Pool Pilot Digital SWCG / SC-36 Salt Cell / Hayward 1 hp pump / Pentair CNC 100 / Solar Heater

Posting Permissions

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