Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 11 of 11

Thread: Rain & Ph

  1. Back To Top    #1

    Join Date
    Mar 2011
    Location
    Grand Rapids, Michigan
    Posts
    274

    Rain & Ph

    I'm thinkin' the rain upped my Ph. Am I crazy? Last weekend I was spot on with my numbers. Just ran a test (TF100) and here's what I got.

    FC 7
    CC 0
    Ph 7.8
    TA 90
    CH 160
    CYA 40

    Went to the pool calculator to see how much acid to add and seen also that it was telling me to add baking soda, too. Won't the soda run up my Ph again? Should I just sit tight a minute & see if the Ph ticks down a bit on it's own? Have had a bunch of rain--had to pump water out 3 times in 2 weeks.

    Thanks all!
    17,500 gal. ABG Doughboy Pool
    1/2 HP Pump/150 sq.ft. Cartridge Filter
    TF100 Test Kit And Speedstir

  2. Back To Top    #2

    In the Industry

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

    Re: Rain & Ph

    pH of 7.8 is at the top end but acceptable. I would leave it alone until it goes to 8.0

    What did you want to lower it to?

    Baking soda has no measurable affect on your pH but you don't need any, either.

    Last, the rain has very little affect on your pH but if it's enough rain and it's far enough away from your pool pH, it could move it a point or two, I suppose.

    A "normal" rain is typically a non-event to a pool although many people seem to think the results will be drastic.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  3. Back To Top    #3
    alanpaul's Avatar
    Join Date
    Aug 2010
    Location
    South Florida
    Posts
    227

    Re: Rain & Ph

    DebO,

    Here in South Florida, we get 5 feet of rain per year, averaging 5-10 inches per month (because we have a dry season in the winter). This week we've had over 6 inches already, and we're forecast to have as much as 5-10 inches in the coming week.

    And the answer to your question, specifically in our environment, is: Yes. When we get a lot of rain, we usually have to add acid to re-balance the pH. Only once in quite a few years do I remember having to raise the pH after a lot of rain.

    Someone once told me that here on the peninsula of Florida, the pH of the rain is affected differently depending on whether it is a storm from the Gulf of Mexico - west, or a storm from the Atlantic Ocean - east. I'm not certain I believe that theory.
    Alan
    Alan in Wellington, FL - near West Palm Beach
    15,200 gal IG, painted plaster, 1988; 200 SqFt cartridge filter, 2013; 1.5 HP 1-speed pump (uprated), 2005; heat pump, 2005;
    soon to repair (dead) SWG AquaRite T-15 cell, 2005, and replace (dead) suction-side cleaner, 2005.
    Almost everything died this winter 2012-'13, and I know we shouldn't complain... but, Arrgh!

  4. Back To Top    #4

    In the Industry

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

    Re: Rain & Ph

    we usually have to add acid to re-balance the pH
    How many points would you say your pH raises after a big rain?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  5. Back To Top    #5

    Join Date
    Mar 2011
    Location
    Grand Rapids, Michigan
    Posts
    274

    Re: Rain & Ph

    I wanted to bump it down to 7.4 or so. Since I joined this site I have become compulsive! We did have a couple major downpours. The kind that make you pull off the road when driving.

    So, thanks for the quick answers. Guess I'll go net the cottons instead!
    17,500 gal. ABG Doughboy Pool
    1/2 HP Pump/150 sq.ft. Cartridge Filter
    TF100 Test Kit And Speedstir

  6. Back To Top    #6
    alanpaul's Avatar
    Join Date
    Aug 2010
    Location
    South Florida
    Posts
    227

    Re: Rain & Ph

    @ Dave S. Duraleigh,
    FYI, It 's not been unusual for our pH of 7.4 or 7.5 to rise anywhere up to 8.0 as it did just this week after more than 4 inches of rain within 36 hours.
    Alan
    Alan in Wellington, FL - near West Palm Beach
    15,200 gal IG, painted plaster, 1988; 200 SqFt cartridge filter, 2013; 1.5 HP 1-speed pump (uprated), 2005; heat pump, 2005;
    soon to repair (dead) SWG AquaRite T-15 cell, 2005, and replace (dead) suction-side cleaner, 2005.
    Almost everything died this winter 2012-'13, and I know we shouldn't complain... but, Arrgh!

  7. Back To Top    #7

    In the Industry

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

    Re: Rain & Ph

    Most pools have an average depth of about 48" or so. A 4" rain would possibly replace a bit less than 10% of the pool water.

    So, it seems to me that rain would have to have a pH up in the teens (I think) to have that kind of influence on the remaining 90% of the 7.4 water??

    I wonder if that SWG was a big contributor somehow.....it just doesn't make sense that rain can be that high.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  8. Back To Top    #8
    alanpaul's Avatar
    Join Date
    Aug 2010
    Location
    South Florida
    Posts
    227

    Re: Rain & Ph

    @ duraleigh
    Yes, it's a puzzle. 4" of rain equates only to an additional 7.4% of water in our pool, and shouldn't have that effect, but often it does.

    I suspect that run-off from the shingle roof and concrete deck (though it mostly drains away from the pool) have some effect as well.

    Our SWG, listed as dead in the signature, is currently non-functional. I'm expecting the replacement Current Limiter to arrive in today's mail.
    Alan
    Alan in Wellington, FL - near West Palm Beach
    15,200 gal IG, painted plaster, 1988; 200 SqFt cartridge filter, 2013; 1.5 HP 1-speed pump (uprated), 2005; heat pump, 2005;
    soon to repair (dead) SWG AquaRite T-15 cell, 2005, and replace (dead) suction-side cleaner, 2005.
    Almost everything died this winter 2012-'13, and I know we shouldn't complain... but, Arrgh!

  9. Back To Top    #9

    Join Date
    May 2013
    Location
    Miami, FL
    Posts
    23

    Re: Rain & Ph

    I concur with Alan, it's been raining pretty hard the last couple days and my ph keeps climbing after adding muriatic.
    pool owner since 2012
    13-15k gallons, kidney shaped,in-ground plaster
    1970s construction, currently undergoing complete renovation
    3 jets, 1 skimmer, 1 dedicated vacuum line, kreepy krauly great white, main drain

  10. Back To Top    #10
    linen's Avatar
    Join Date
    Jul 2010
    Location
    Twin Cities, MN
    Posts
    8,649

    Re: Rain & Ph

    As duraleigh pointed out, the ph of the rain itself (usually it is acidic with low TA, netting little effect) does not change pool ph much.

    Rains like you are having can cause significant aeration, which of course raises ph.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

  11. Back To Top    #11
    Patrick_B's Avatar
    Join Date
    Jun 2011
    Location
    Midland TX
    Posts
    15,001

    Re: Rain & Ph

    I have to agree with Dave an Linen here. And remember moving the pH one whole point say from 7.0 to 8.0 is a really HUGE change.

    The pH scale is a log of ten, so a pH of 7.0 is TEN TIMES more acid than pH 8.0.

    Unless rain is washing a lot of something into the pool, I don't see how even a good rain would change pH much at all.
    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

Posting Permissions

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