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Thread: HELP!! PB put in 3gals of Acid and killed my pH & TA!!!

  1. Back To Top    #1

    Join Date
    Feb 2008
    Dripping Springs, TX

    HELP!! PB put in 3gals of Acid and killed my pH & TA!!!

    The PB came back yesterday to sand my coping because it was so dirty, and that was the last "finishing touch" they had remaining on my 4-week old (new) 10KGal pool/spa.

    I knew it was going to make a mess (limestone dust EVERYWHERE) and indeed it did. I had my filter off when they sanded, and then the knucklehead sander guy turned the filter pump back on when he left. I discovered it an hour later and called my PB and he told me to shut it off and let it settle and that we'll vac it today.

    So today comes and by the time I wake up, he is already out there and has vac'd my pool. I get out of bed, toss some clothes on, and head outside and discover not only did he vac my pool (he did a great job, btw - little to no limestone powder residue on the pool walls/floor) he also decided to toss in a few gallons of acid.. 3 gallons to be exact.. (according to the pool calc this lowers my pH by 8.0!!! ***!?!?!). I guess he thinks he is still in the "Acid start up" phase of helping finish my pool. How nice of him. At least it was his own Acid, and not from my stash (in a deck box right by the pool).

    In any event, he had vac'd and we also cleaned my filter cartridges just, and then based on his suggestion, I let the acid sit for a few hours "to help loosen up any limestone powder stuck on the walls", maybe 5 hours.. I then test everything and confirm my pH is terribly low (It is yellow, so it could be 6.7 or less, way less perhaps?!?!) which is no surprise BUT my TA is now showing 0ppm (I have to add 0 drops to make it change colors as it was already changed). I tested them both again just to make sure - same results!!!!!!! AARGH!

    So I hop on the and find I need to throw in some Borax.. About 4lbs worth (a whole box basically) to get my pH up from maybe 6.7 to the 7.5 range.. So I do. And the filter remains on all day so it mixes well.

    I come back from dinner tonight, which is about 5 more hours later, and re-test, this time with my new AquaCheck Select 6-way strips. pH is still in the 6.7ish range, and TA appears to be 0ppm still.

    So now I'm really frustrated..

    I threw in some more Borax, about 1.5lbs, and will retest in the morning. I'm not so worried about my pH because I'm certain I can get that back up.. But I'm really bummed about the TA... If you follow this forum, you'll see I just spent the better part of the past week dumping in about 19lbs of Baking Soda to get the TA up to 100ppm. I finally had it to 100ppm like 2 days ago. And it was steady for at least 24 hours.. I'm really worried that my TA is gone now, and that is that, and that I need to toss in another 19lbs of Baking Soda... COULD THIS BE?!?!?!?!?!

    Also, I hope the limestone powder/dust isn't doing anything bad, e.g. reacting with the acid in some way..

    Any ideas on how to EXPEDITIOUSLY resolve this are MUCH APPRECIATED!!!!

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD
    My Pool Calculator is not accurate for very large PH changes. Quantities can be much higher or lower when dealing with extremely high or low PH and/or TA.

    It will take about 8 1/2 lbs of soda ash/washing soda, or about 17 lbs of borax to neutralize each gallon of acid. Some of the acid will have reacted with the limestone dust and be neutralized already, so the actual numbers will be lower and there is no easy way to get an good measure (unless you have the base demand test that comes in some of the Taylor kits). If you use soda ash/washing soda to raise the PH it will also raise the TA significantly (probably by too much if you use all soda ash), while borax will raise the TA some but probably leave it too low.

    The acid will help dissolve the limestone dust, and probably a little bit of your plaster, and both of those processes will raise your CH level. When you get the PH under control test your CH level to see where you ended up.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  3. Back To Top    #3

    Join Date
    Feb 2008
    Dripping Springs, TX
    This morning's readings:

    CL: 2.5
    pH: 6.7
    TA: 30ppm
    CH: 420ish

    So it looks like the acid is being neutralized.. slowly.. I tossed some more Borax in to bump up the pH and the TA a little, and the borates some while I'm at it.

    I think I need a few lbs (maybe 12) of baking soda now, though, to get my TA back up to 100ppm..

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