Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: pH for a dark bottomed plaster pool?

  1. Back To Top    #1

    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    282

    pH for a dark bottomed plaster pool?

    I have a plaster/gunnite pool that is a dark, dark, dark blue color. I also have a SWG.

    The paperwork from the pool builder said for "dark bottom plaster pools keep the pH at 7.2", but the guidance from TFP in the Salt Water Generator section says you should keep it at 7.5 - 7.8.

    Who is right and why? (I think I know the answer, but why would the pool company tell me to keep the pH so low?)

    It's a new pool so the pH is constantly rising, but I'm just trying to figure out where I should try to keep it.

    Thanks!
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

  2. Back To Top    #2

    Join Date
    Nov 2010
    Location
    Calera, Al
    Posts
    271

    Re: pH for a dark bottomed plaster pool?

    With a new plaster pool The ph will constantly rise. I try to keep mine at the lower end of the scale and have to add ma every few days to combat the rise. We have hard water, and I dont want calcium scale in the pool like on every faucet in the house...
    17,000 gal, IG Gunite Diamond Brite plaster Kidneybean,w/7x11 tanning ledge& 3x5 swimout bench,244T 300lb Hayward Pro high rate sand filter(63 GPM) , Hayward 1Hp Super Pump w/3/4 hp booster pump, Polaris 280, Laars Lite 2 175k N/G Heater, Tf-100, Speed stir

  3. Back To Top    #3

    In the Industry

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

    Re: pH for a dark bottomed plaster pool?

    Follow the instructions of the PB. There is no HUGE difference there so do it his way.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4

    Join Date
    Mar 2011
    Location
    Houston, Texas
    Posts
    413

    Re: pH for a dark bottomed plaster pool?

    Here's my experience with grey plaster. My pool is about 6.5 months old and the pH is still rising every day. I go through about a gallon of MA each week. My pH will reach the high 7s to low 8s until I add acid to take it back down to around 7.2. My CH is on the high side no mater whose test you believe (TF-100 800; pool plaster contractor 570; Leslie's 400) and over the last couple of months I have developed scaling. The scaling clearly is the result of my CH being too high coupled with the pH above 7.5 (even though it's not at that level for very long). My guess is that because scaling is so obvious on a colored plaster/pebble finish that the plaster companies tell us to keep the pH at the lower range. Wet Edge recommended 7.2-7.4 for my pool.
    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

  5. Back To Top    #5
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: pH for a dark bottomed plaster pool?

    The normal Pool School guidance of PH between 7.5 and 8.0 does not apply during the first month with fresh plaster. During the first month about the best you can hope for is to lower PH to 7.2 as often as possible and hope it isn't above 8.0 by the next time you have a moment to look at the pool.

    Once several weeks have passed and things settle down you need to balance the water so there won't be calcium scaling and there won't be calcium pitting. There are several ways of doing that, PH high, PH low, PH in-between. The most stable way seems to be with the PH between 7.5 and 7.8 and all of the other levels adjusted to make that work. Trying to keep the PH too low will result in wild swings in the PH, which isn't good.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  6. Back To Top    #6

    Join Date
    Jan 2010
    Location
    Northern Virginia
    Posts
    282

    Re: pH for a dark bottomed plaster pool?

    Thanks all!

    Jason - the pool was first opened late last fall and then immediately closed. We reopened it very early this spring and the pH has been still shooting up like a rocket. I assume this is normal and your "first month" comment was more of a guideline than an absloute?

    Thanks again!
    700 sq. ft./30,000 gal, gunite pool; 48 SF DE filter; 1.5 HP pump; Salt Water Generator; Solar Heat

  7. Back To Top    #7
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: pH for a dark bottomed plaster pool?

    The "first month" can be postponed by cold temperatures or last longer than a month, so yes a guideline.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

Posting Permissions

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