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Thread: Numbers from my pool - looking for input

  1. Back To Top    #1

    Join Date
    Aug 2007
    Location
    Denton, TX
    Posts
    48

    Numbers from my pool - looking for input

    From my first test with the TF test kit on 8/22/07 - keep in mind my filter was broken, we'd just moved in to the house, and the previous owner was using trichlor tabs in a floating feeder.

    FC .5
    CC .5
    TC 1
    pH 7.2
    TA 120
    CH 1160
    CYA way way over 100
    Temp 85

    Numbers from 9/25/07 - after new filter, several partial drain & refills ($200+ water bill - OUCH!) & BBB method

    FC 6
    CC 0
    TC 6
    pH 7.5
    TA 100
    CH 340
    CYA 60
    Temp 82

    The water is clear & sparkling, no chlorine smell.

    According to Jason's pool calculator, I have a CSI of .34

    When I run the polaris cleaner overnight, I'll often find 1 - 1 1/2 cups of white, grainy material in the bag in the morning. I'm wondering if this could be due to the high CH, or if it's just bits of my pool's finish that are coming off.

    The pool is about 20 years old, and there appears to be a piece of rebar showing through the finish in one spot. At first I thought it was just a stain, but I put on a diving mask and went down to have a look. I could see fuzzy tendrils of rust on top that brushed away with my hand and can also feel where the finish is missing.
    13K gal - IG gunite/plaster - 1 1/2 HP pump - 300lb. sand filter - SWCG
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  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879
    Congratulations on the dramatic CH and CYA reductions and clear water!

    When I run your most recent numbers I get a CSI of 0.05. Perhaps there is a typo in either the numbers you posted or the numbers you entered when calculating the CSI?

    If the plaster is 20 years old it is not surprising if it is failing. That would fit with rebar showing through and bits of plaster showing up in the cleaner. Even significantly newer plaster could have the symptoms you describe with some bad chemistry at some point in the past. You can probably get away with leaving it as is for quite a while but eventually you will have to look at replastering.
    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

  3. Back To Top    #3

    Join Date
    Aug 2007
    Location
    Denton, TX
    Posts
    48
    When I run your most recent numbers I get a CSI of 0.05. Perhaps there is a typo in either the numbers you posted or the numbers you entered when calculating the CSI?
    D'oh!

    You're absolutely right. Last night (when I ran the numbers through your pool calc) my pH was 7.8 so I added acid & retested this morning. My current CSI is .05.

    What does replastering entail? Do they spray / apply the new over the old? Or is the old removed first?

    PS - I'd been meaning to make a donation for the poolcalc, since I use it several times a week. Look for a contrib from me today.
    13K gal - IG gunite/plaster - 1 1/2 HP pump - 300lb. sand filter - SWCG
    Support TFP!

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