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Thread: High Acid Use

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    High Acid Use

    In my reading here I understand some pools just use a lot of acid and at 19 months old my plaster may not be fully cured and adding to the problem. However I only used about half as much acid last year and the SWG was just added in May so I am thinking it is the major culprit to my high acid demand. One thing I have no clue as to why it is happening, my TA drifts up with the pH. I started this spread sheet posted by another TFP member when I got my TF100 Kit. (I was previously using a Taylor K-2005.) Blanks mean test not taken. We have had a little rain around the 12th. Any suggestions on how I can lower the acid demand? How low can I take TA safely? 30-40? Why is TA drifting?
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    22,000 Gunite, Cart Filter, Aquarite SWG

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    frustratedpoolmom's Avatar
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    Re: High Acid Use

    I don't think you should go lower on the TA than 60.

    Do you have high TA in your tap water, and do you have an autofill system? Or have you manually been adding water that could be increasing the TA level?
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    Mod Squad JohnT's Avatar
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    Re: High Acid Use

    TA moves with pH. If you compare the pH reading with the TA reading, you'll see that it's pretty consistent.
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    Re: High Acid Use

    Do you have a constant source of aeration, such as a spillover spa, waterfall, wind or have your returns adjusted to break the surface? Rain will also be a source of aeration. As I recall, these can lead to an increase in acid demand. What is your actual MA usage and how often do you add it? I noted you recently brought up your CYA to the recommended range. That will go a very long way to reduction in the SWG percentage and keep your acid demand a bit lower.
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    mas985's Avatar
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    Re: High Acid Use

    The only way TA can rise is if something is being added to the pool. This is usually casued by the fill water as FSP pointed out and will usually cause a rise in PH as well but the SWG will make it even worse due to the aeration caused by the Hydrogen bubbles. So if you experience a rise in PH without a rise in TA, it is likely to be the SWG and other sources of aeration. If you are getting a rise in both TA and PH, it is probably both the fill water and SWG/aeration causing the problem.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
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    Re: High Acid Use

    My fill water has high TA but none has been added. TA is drifting up with pH. I say again, no fill water has been added. The only thing that has been added to the pool in the last 2 weeks is MA. I have no water features, no aeration, no kids spashing, just the SWG. There was a small amount of rain on the 12th but the TA held at 60 after that event. 4 gallons of MA in a 2 week period just sound crazy...
    22,000 Gunite, Cart Filter, Aquarite SWG

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    Re: High Acid Use

    TA is drifting up with pH.
    As JohnT posted earlier,
    TA moves with pH.
    pH goes up, TA goes up.....pH goes down, TA goes down
    Dave S. - Forum owner
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    Re: High Acid Use

    Right, and mas985 said:

    Quote Originally Posted by mas985
    The only way TA can rise is if something is being added to the pool. This is usually casued by the fill water as FSP pointed out and will usually cause a rise in PH as well but the SWG will make it even worse due to the aeration caused by the Hydrogen bubbles. So if you experience a rise in PH without a rise in TA, it is likely to be the SWG and other sources of aeration. If you are getting a rise in both TA and PH, it is probably both the fill water and SWG/aeration causing the problem.
    so, I'm still confused...
    22,000 Gunite, Cart Filter, Aquarite SWG

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    JasonLion's Avatar
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    Re: High Acid Use

    Do you have an auto fill system, or have you been adding water to the pool manually? If so, you should test your fill water to see what the TA level is.

    I wouldn't ever lower TA below 50, and 60 is safer.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: High Acid Use

    Hi Jason, Like I said before no fill water has been added at all. None, Nada. There is no auto fill. I guess I'm lucky TA is drifting with pH, with the amount of MA added it should be close to zero!
    22,000 Gunite, Cart Filter, Aquarite SWG

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    Re: High Acid Use

    Quote Originally Posted by duraleigh
    pH goes up, TA goes up.....pH goes down, TA goes down
    Not always. PH can rise without TA going up such as when aeration occurs. However, when TA rises, PH usually goes up with it. Also, when an acid is added both TA and PH will drop.

    But like I said before, you cannot get a TA rise without something (carbonates and bicarbonates) being added to the pool somehow. Aeration does not affect TA. Borax, Baking Soda, Soda Ash, etc will all raise TA to some extent as well as PH but TA does not rise on its own.
    Mark
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    Re: High Acid Use

    have you looked at the concentration on the acid bottles lately? some people have found their stores getting lower strength MA for the same price.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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    Re: High Acid Use

    Does your pool have rocks as the edging? Have you seen any wearing of those rocks, if so?
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

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    Re: High Acid Use

    No rocks on the edges, acid is 34%. It has to be the plaster still curing, I guess... Maybe I just need to give it a few more months? It was only plastered Dec 07...

    BTW, thanks to you all for chiming in. The folks at Ace hardware are looking at me weird when I keep buying acid 6 gallons at a time! Luck for me, they are selling them for under $4 a gallon.
    22,000 Gunite, Cart Filter, Aquarite SWG

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    reebok's Avatar
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    Re: High Acid Use

    wow good price. mine was plastered 12/07 also. it's been plenty of time imo.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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    Re: High Acid Use

    New numbers for today

    PH 7.8
    TA 50
    CH 550
    Free CL 4.8
    CC .2
    CYA 60
    Borates 30
    Salt 3000

    PH as risen .2 a day, every day no matter what the SWG is set on. I went 2 days with it off and the rise is the same. This is the first week that TA did NOT go up with PH. Normally TA will come up with ph, when ph hits 8 ta is up to 80. We have had a butt load of rain the past few day so I can see why CYA has fallen off a bit. CH has gone up from 2 months ago, it was right at 380 for the longest time so I have not been checking it. It is now 550. I checked it twice. Yes, it is a TF test kit and Apollo stirrer. My routine is to let the ph get to 8 and add a half gal of acid. Then repeat every 2 days. If I'm going to be out of town, I'll let it get to 8 then add a gallon which gets it down to near 7. There it will be good for 5 days. Is adding so much acid all the time doing something to the plaster making CH go up? Is something blowing into the pool I can't see effecting the water? Plaster was done in Jan 08 and when using the off-line CL with pucks, PH would come up but slowly. So little, I don't remember putting acid in very often at all. Anyone else seeing an acid demand like this with 22 month old plaster and a SWG?
    22,000 Gunite, Cart Filter, Aquarite SWG

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    polyvue's Avatar
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    Re: High Acid Use

    Quote Originally Posted by frankgh
    New numbers for today

    PH 7.8
    TA 50
    CH 550
    Free CL 4.8
    CC .2
    CYA 60
    Borates 30
    Salt 3000
    As first responder to your most recent post I'll go out on a limb a bit... don't know why your Calcium Hardness increased since your original July post, but it's well outside recommended levels. My first instinct would be a partial drain/refill to get it down (check your fill water first to be sure CH is not some ungodly high figure, say, over 300.)

    Second thought: Maybe your pool likes a higher pH (not very scientific, I know) -- have you run the numbers through the Pool Calculator? If you're reasonably balanced, maybe the acid demand isn't something to worry much about.

    Other, wiser heads on this forum may wish to add or subtract from this rumination. If they object to these observations, feel free to discard them.
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    dmanb2b's Avatar
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    Re: High Acid Use

    Good stuff Poly

    This thread has my head scratching

    On the CH 550 is high but manageable, just don't let your PH go beyond 7.8. Letting it go to 8, like you have in the past could now cause calcium scaling.

    On your TA issue, given your pool has had time to cure, I'm thinking there may be an issue with your TA test numbers. Can you do me a favor and repeat the TA test, but before each drop added, wipe the dropper with a damp paper towel? There have been reports that static charge has affected the size of the re-agent droplets. Try that and see if your TA is really 60.

    Hope that helps
    24'x52" AGP (13,500 Gallons), Intex SWG, (2)Solar Bear 4x20 panels, Hayward S220T Filter, 1/2hp Pentair Superflo

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    Re: High Acid Use

    This thread has my head scratching
    Yeah, me, too.

    I don't think the redo of the TA test will shed any light. The issue with that test is that the R-0009 reagent (and only that reagent) has a tendency to develop a static charge between itself and the bottle that contains it.

    The result is that the drops "leap" from the bottle before they are fully formed.....causing the drops to be smaller. The result is a false high test result.

    Wiping the dropper tip seems to consistantly cure the problem. I can't think of an instance where that issue would cause a low TA result.

    It's w-a-a-a-y above my pay grade but can a condition exist within the plaster where it never really cures (or cures abnormally slow) so is constantly throwing off calcium and creating a pH rise?
    Dave S. - Forum owner
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    Re: High Acid Use

    Quote Originally Posted by duraleigh
    It's w-a-a-a-y above my pay grade but can a condition exist within the plaster where it never really cures (or cures abnormally slow) so is constantly throwing off calcium and creating a pH rise?
    Quote Originally Posted by Sherlock Holmes
    How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
    So if there has been no fill water added, no features to dissolve and rain water generally does not add calcium (it can raise PH though), then the only possibility is the pool surface dissolving which is not a good situation.
    Mark
    Hydraulics 101; Pump Ed 101; Pump and Pool Spreadsheets; Pump Run Time Study; DIY Acid Dosing; DIY Cover Roller
    18'x36' 20k plaster, 1/2 HP 2sp pump, Aqualogic PS8 SWCG, 420 sq-ft Cartridge, Solar, 6 jet spa, 1 HP jet pump, 400k BTU NG Heater

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