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

Thread: Calcium Hardness raising. Why?

  1. Back To Top    #1
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Calcium Hardness raising. Why?

    This is my first post so go easy on me. Pool was finished last October and I've been following the TFP guidelines for my chemistry.
    Using the TF-100 kit.
    Current levels
    FC-3
    PH 7.5
    TA 60
    CYA 80
    Salt 3300
    CH-540

    I usually have to add acid a couple times a week to keep th PH under control. The CH has been steadly climbing and I don't know why. I haven't noticed any scaling, but the clarity is a little off.

    My question is what is causing it and is this a real problem.

    I'm not really interested in draing half the pool water. As I'm in South Florida lots of rain should be diluting it. (it worked for my CYA and Salt)

    Thanks
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  2. Back To Top    #2
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
    Posts
    10,045

    Re: Calcium Hardness raising. Why?

    Welcome to the forum

    Have you tested the fill water for CH?

    Have you used cal-hypo?
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
    Posts
    10,045

    Re: Calcium Hardness raising. Why?

    btw, you should bump up the FC and maintain between 4 and 6, and never below 4. This could be the reason for dull look, too.

    Nice test kit
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  4. Back To Top    #4
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Re: Calcium Hardness raising. Why?

    Quote Originally Posted by Butterfly
    Welcome to the forum

    Have you tested the fill water for CH?

    Have you used cal-hypo?
    Fill water just tested =50.

    Never added cal-hypo just some cya and salt

    I'll bump up the SWG a bit. Going to clean it to for the first time
    Zero CC s BTW
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  5. Back To Top    #5
    Butterfly's Avatar
    Join Date
    May 2007
    Location
    South Carolina
    Posts
    10,045

    Re: Calcium Hardness raising. Why?

    Well, maybe testing error. Try the Extended Test Kit Directions using 10 ml of pool water, 10 drops of R-0010, 3 drops of R-0011L, and multiply the number of drops of R-0012 by 25 to get your CH level. Complete directions here:

    extended-test-kit-directions-t25081.html
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  6. Back To Top    #6
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Re: Calcium Hardness raising. Why?

    Using modified test, results... about the same, 22 drops= 550

    Is having Calcium Hardness this high really a problem?
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  7. Back To Top    #7

    Join Date
    Mar 2011
    Location
    Houston, Texas
    Posts
    413

    Re: Calcium Hardness raising. Why?

    I have a similar issue. My fill water is CH 150, but it seems my CH rises even when I haven't added water for a few months.

    I manage my TA and pH to keep my CSI slightly negative so it hasn't been a problem.
    9,200 gal. Gunite Luna Quartz French Grey pool with spill over spa, two fountains on tanning ledge (rarely used)
    Pentair Whisperflo 2HP, Pentair CCP Cartridge 420 Sq. Ft., Polaris 280 with booster pump
    Pentair EasyTouch 4, RayPak LoNox 266k Natural Gas heater, Aqua Rite SWCG T Cell 9, Borates, TF-100 test kit

  8. Back To Top    #8
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Calcium Hardness raising. Why?

    It can become a problem. Some is likely coming out of the plaster, and the rest is due to evaporation and refilling.

    Don't you get rain down there in the summer? Divert a downspout into the pool and dilute it. Warning: the first inch or so will sweep all the dust and debris in, so give the gutters a chance to clear before you start filling.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  9. Back To Top    #9
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Re: Calcium Hardness raising. Why?

    Yes we get plenty of rain.
    So much so that for awhile it looked like I had a zero edge pool.
    That's why I'm surprised its getting so high.
    I always thought....
    "The solution to pollution is dilution"
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  10. Back To Top    #10

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Calcium Hardness raising. Why?

    Are you adding acid slowly over a return flow and perhaps brushing in the area where you add acid to ensure thorough mixing? If not and you add it too quickly in one place, then is there any noticeable deterioration (pitting) of the plaster in the area where you are adding acid? You might be dissolving some of your plaster (the calcium carbonate portion) into the water. Hopefully not, but I'm just putting that out there as a possibility. Seems unlikely though since the quantity would be rather large so would normally have to involve a huge amount of surface area of the pool, not just one place where you've been adding acid.

    The CSI is negative (-0.4) though not extremely low and if this was soon after the re-plaster then I could see how that might dissolve new plaster more readily, but it's been long enough that I would have expected that to have cured by now. I don't think the cloudiness is due to calcium carbonate since your CSI is negative so your water is not over-saturated. Basically, your high CH isn't actually too high given your other water parameters. I would not try and lower it. It's more likely that your FC of 3 ppm is not enough for your CYA level of 80 ppm and you may be starting to get algae so may need to shock the pool and then keep a minimum FC (after you come back down from shocking) of 4 ppm.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  11. Back To Top    #11
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Re: Calcium Hardness raising. Why?

    I'm usually pretty careful about adding acid. Mix it in a bucket of water an pour slowly into the deep end. Usual dose is about 20 oz.

    Cleaned the SWG yesterday, added a little bleach, and let the filter run all night with the Great White cleaner scrubbing away.
    This morning's results

    TC/FC 6
    PH 7.5
    TA 70
    CH 500
    temp 87
    Visually water looks clearer.

    The other thing I thought of is, after a couple of days of heavy rains the water does overtop the coping (which is natural travertine marble) I don't drain it down just let nomal activity splash it out.
    Is there a chance the water is breaking down the stone ? It looks ok no noticeable degrading,
    Just a thought.
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  12. Back To Top    #12

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: Calcium Hardness raising. Why?

    Rain does tend to contaminate pools depending on what gets washed in, but in your case it does sound more like algae growth that was getting started and that the elevated chlorine level is killing it off. Shocking the pool would kill it off faster (and is what would normally be recommended), but so long as you are making progress you're doing OK -- just don't let the FC drop too low or the algae will grow faster than chlorine can kill it. If you find you get stuck, then shock the pool by elevating the FC to a much higher level than you are doing.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  13. Back To Top    #13
    Joe_Fire's Avatar
    Join Date
    Sep 2012
    Location
    South Florida
    Posts
    8

    Re: Calcium Hardness raising. Why?

    Thanks for the help chem geek.
    I didn't have enough chlorine to shock to 21 as the Pool Calculator indicated. So I set the SWG to "Super Chlorinate" and let it run all night.
    This morning FC is at 21ppm.
    I shut the SWG off.
    Should I keep it off untill the Chlorine comes down to 6?
    Or just leave it on it's normal setting
    Water looks good btw.

    Also what effect on the CH would adding borates have. I've read about the benefits of 50ppm and have considered doing it. But I think I'll wait a week or 2
    16K Free Form Diamond Brite, 8' sunshelf,deckjets,and bubbler,Travertine pavers
    Hayward C17502 Cartridge Filter, 2HP Variable pump, Turbocell T-Cell 15 SWG, Aquaplus controller

  14. Back To Top    #14
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Calcium Hardness raising. Why?

    Quote Originally Posted by Joe_Fire
    Thanks for the help chem geek.
    I didn't have enough chlorine to shock to 21 as the Pool Calculator indicated. So I set the SWG to "Super Chlorinate" and let it run all night.
    This morning FC is at 21ppm.
    I shut the SWG off.
    Should I keep it off untill the Chlorine comes down to 6?
    Or just leave it on it's normal setting
    Water looks good btw.

    Also what effect on the CH would adding borates have. I've read about the benefits of 50ppm and have considered doing it. But I think I'll wait a week or 2
    Leave the chlorinator on. The shock process is about maintaining high FC for a long period of time, not a one-time megadose.

    It might be time to reread pool-school/shocking_your_pool
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

Posting Permissions

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