Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 12 of 12

Thread: Large Pool

  1. Back To Top    #1
    pinguy's Avatar
    Join Date
    May 2015
    Location
    Pennsylvania
    Posts
    515

    Large Pool

    Is low CH a problem for a painted concrete surface?

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

    Re: Commercial Pool Fun

    Iron in the water will turn very green when chlorine is added to it. Sometimes you get lucky and at SLAM levels, it'll actually precipitate the iron out of the water and the filter will catch it. But, that doesn't always happen.

    Low CH isn't a concern for painted pools as long as there is no concrete exposed.
    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
    pinguy's Avatar
    Join Date
    May 2015
    Location
    Pennsylvania
    Posts
    515

    Re: Commercial Pool Fun

    Quote Originally Posted by Bama Rambler View Post
    Iron in the water will turn very green when chlorine is added to it. Sometimes you get lucky and at SLAM levels, it'll actually precipitate the iron out of the water and the filter will catch it. But, that doesn't always happen.
    Curious that the Taylor iron kit didn't pick up on it.

    I'm assuming a sequestriant is the only option if adding CYA and Slamming does not clear things up?

  4. Back To Top    #4
    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,337

    Re: Commercial Pool Fun

    The big problem with the metal tests is that they give a lot of false negatives. A lot of times metals won't show up on the tests even though you know they're in the water.

    Since it's always shown up and always gone away on it's on, I'd say raise the FC to slam level and keep it there for a while and see if it precipitates out.

    If it doesn't, then you're correct, sequestrant is about the only option.
    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

  5. Back To Top    #5

    Join Date
    May 2016
    Location
    Amarillo, Texas
    Posts
    38

    Re: Commercial Pool Fun

    If you have iron, two methods I've seen to remove it in drinking water is aeration and sodium permanganate. For example, here is a picture of some aerators just for the purpose of Iron and Manganese removal. I have also seen pure oxygen pumped into the bottom of a reservoir. If it is Iron, some method of aeration may be a means to precipitate it out. If it is coming from the well water, it may be avoided in the future by infusing air into the line as it is pumped (maybe create a venturie to suck in some air)
    plant aerators.jpg

  6. Back To Top    #6
    pinguy's Avatar
    Join Date
    May 2015
    Location
    Pennsylvania
    Posts
    515

    Re: Commercial Pool Fun

    Interesting. A purifier/softener is in place, but I have a feeling it does not take care of iron.

    It's disappointing the Taylor Iron kit is not reliable, its not cheap!
    Helpful Links: Pool Chemistry 101 - Recommended Levels - Recommended Chemicals - FC/CYA Chart - SLAM Instructions - Pool Math
    Test Kits:
    TF-100 - Taylor K2006 - SpeedStir Upgrade - Taylor K-1766 Salt Test
    My Pool:
    28k IG built May 2015 - Autopilot SWG - Pentair VS Pump/DE Filter/Heat Pump

  7. Back To Top    #7

    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Location
    Sebring, Florida
    Posts
    30,077

    Re: Commercial Pool Fun

    Pchase,

    I am not sure that method is practicable for pools. The aeration drives out the iron by precipitation, but what really happens is the air drives up the pH of the water and it is the high pH that precipitates the iron.

    I imagine it drives the pH so high that now you have what might be an insurmountable pH issue in your pool.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  8. Back To Top    #8

    Join Date
    May 2016
    Location
    Amarillo, Texas
    Posts
    38

    Re: Commercial Pool Fun

    Quote Originally Posted by duraleigh View Post
    Pchase,

    I am not sure that method is practicable for pools. The aeration drives out the iron by precipitation, but what really happens is the air drives up the pH of the water and it is the high pH that precipitates the iron.

    I imagine it drives the pH so high that now you have what might be an insurmountable pH issue in your pool.
    On large plants, I see a once through system, so the incoming water is all treated as it enters the plant and not recycled through the tank. You want a pH of at least 7.2 with a target of 7.5 to 8.0. With this, you don't really see an increase. Recycling around a pool would probably need to be answered in how much air is needed. I have a calculation for that somewhere.

    I did a quick search on venturi injectors and found this one for chemical injection into pools. http://mazzei.net/pool/ It can be used for adding liquid chemical or air.

  9. Back To Top    #9

    Join Date
    May 2016
    Location
    Amarillo, Texas
    Posts
    38

    Re: Commercial Pool Fun

    I ran a number of about 2 cfm/transfer efficiency of air per gpm of water assuming Fe around 10 ppm.

    But as I think about it, the time to treat is the fresh water on the fill because once it is in and Chlorine added, it's probably converted to something like FeCl and may prevent it from precipitating out as iron Hydroxide. When it is filled, something like the venturi mentioned and/or anything to splash things around and get air mixed in (stair step, spay into the air, etc.) or if it is filled the diffusion before any chemical treatment outside of a possible pH adjustment. That should precipitate it out and then run the filter to capture it before chlorination.

  10. Back To Top    #10
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Commercial Pool Fun

    Yes, Iron can tint the water green. Really it's pale yellow-orange but the blue pool makes it look green.

    People have had pretty good luck lining the skimmers with paper towels or polyester pillow stuffing. When it gets all rusty, throw it away.
    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!

  11. Back To Top    #11
    pinguy's Avatar
    Join Date
    May 2015
    Location
    Pennsylvania
    Posts
    515

    Re: Commercial Pool Fun

    Quote Originally Posted by Richard320 View Post
    Yes, Iron can tint the water green. Really it's pale yellow-orange but the blue pool makes it look green.

    People have had pretty good luck lining the skimmers with paper towels or polyester pillow stuffing. When it gets all rusty, throw it away.
    - - - Updated - - -

    Any sequestrient recommendations if the green gets worse when I add chlorine?

  12. Back To Top    #12
    pinguy's Avatar
    Join Date
    May 2015
    Location
    Pennsylvania
    Posts
    515

    Re: Commercial Pool Fun

    Read that Phosphate-acid type sequestering agents are best to use.

Posting Permissions

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