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Thread: lowering TA without overshooting

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    lowering TA without overshooting

    I'm currently working on lowering my TA to add borates eventually also. I'm curious, how do I prevent overshooting my TA goal? I've been testing my TA with a 10mL sample, in 25ppm increments. I'm between 100 and 125 now, and figured once I test between 75 and 100 I'll start testing with a 25ml sample. Up until now, I've just been dumping as much MA as PoolMath tells me I need to get my pH down from wherever it is to 7. As I approach 60 though, I'm going to want to try to dose it just right, and PoolMath doesn't seem to tell me how much MA I need to get down to a certain TA. It just tells me to knock my ph down and aerate.

    17,500 gallon IG Vinyl
    Pentair Tagelus TA60D Sand filter
    Pentair Challenger 1.5HP pump CFII N1 1.5A
    Taylor K-2006-A, Stenner 45MPHP10 auto chlorine feed

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    Mod Squad pooldv's Avatar
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    Re: lowering TA without overshooting

    It doesn't really matter a lot. TA is easily raised with baking soda.
    Pool School - Recommended Pool Chemicals
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    Re: lowering TA without overshooting

    ahh, ok, fair enough. I'll just keep going as is, get as close to 60 as possible and use poolmath to figure out how much baking soda I need to get me back where I need to be if I overshoot. Thank you!

    Also, I decided I'm going to start testing TA with a 25ml sample as soon as I get home from work this afternoon. With finer detail in my data, hopefully I can see how much my TA is dropping each time and use that info to prevent overshooting.

    17,500 gallon IG Vinyl
    Pentair Tagelus TA60D Sand filter
    Pentair Challenger 1.5HP pump CFII N1 1.5A
    Taylor K-2006-A, Stenner 45MPHP10 auto chlorine feed

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    Re: lowering TA without overshooting

    So, I got home and tested with a 25ml sample and found that I was down to 70ppm TA. My pH hadn't risen much, only up to 7.2 may 7.3. I went ahead and added 2 cups of MA to put it back about 7 flat for ph. I'll retest in the morning, but if my pH is rising slow with aeration, would it be horrible to add some borax to get it back up? I know I don't want to add borates to the pool until I know I have a good stable TA and pH, but would adding just enough to get my pH up hurt?

    17,500 gallon IG Vinyl
    Pentair Tagelus TA60D Sand filter
    Pentair Challenger 1.5HP pump CFII N1 1.5A
    Taylor K-2006-A, Stenner 45MPHP10 auto chlorine feed

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    Re: lowering TA without overshooting

    Maybe just see whether your pH has stabilised and not actively aerate. I would just let it be and see how things go from there.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
    K-2006

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    Re: lowering TA without overshooting

    Is leaving it at 7 to 7.2 bad for my liner or anything? It throws my CSI score off, and is out of the recommended levels. But perhaps it'll drift up on it's own eventually.

    17,500 gallon IG Vinyl
    Pentair Tagelus TA60D Sand filter
    Pentair Challenger 1.5HP pump CFII N1 1.5A
    Taylor K-2006-A, Stenner 45MPHP10 auto chlorine feed

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    Re: lowering TA without overshooting

    The best thing to do is let pH find it's happy place in the recommended range- should be fine where you have it at the moment.

    All things being equal It will tend to go up anyway in the absence of MA additions.

    CSI is not a big deal with a vinyl pool as it is about the water trying to dissolve the calcium out of plaster pools- obviously not a problem for you. A higher positive CSI score is more of a concern with calcium scaling.
    11 000 gallons, IG, Fibreglass, Monarch Sand Filter, Davey Typhoon C100M 1HP pump, Davey Chloromatic Mc16CTO ESR SWG, Davey Pool Wall Climba Robot, Daisy Solar Cover,
    K-2006

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    Mod Squad pooldv's Avatar
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    Re: lowering TA without overshooting

    Adding borax to raise PH will also raise TA. Use Poolmath Effects of adding Chemicals to see what adding various chemicals will add to your water.

    It is actually good that it is harder to raise PH, it is stabilizing. PH at 7.2 is OK for your liner, 7.0 is a tad low.

    Jezza has it right. As long as CSI is negative you are OK in a vinyl pool. It doesn't matter how negative it is because you don't need to worry about etching. That only applies to plaster pools.
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    2012 build and pics, 20k gal gunite, black onyx pebblesheen, OK flagstone, IntellifoVS, cart filter w/Pleatco, IC40 SWG, Solartouch, 5 12'x4' solar panels, HP50HA heat pump, 8mil solar cover, borates, TF-100 test kit, SONOS, Doheny's Discovery Robot, hot tub on bleach

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    Re: lowering TA without overshooting

    Awesome, thanks everyone. I very much appreciate the help!

    Last night I left my spray in the air aerator running, and this morning before leaving to work, I checked the pH. It was about 7.2, maybe 7.3. So I turned the aerator off and left to work. For some reason I was afraid the pH may be way too high if I let it run all day...though that's probably not the case. I'll check my TA when I get home (didn't have time for that this morning) and hope to find it at 60. If not, I'll probably add another cup or two of MA until I can get it to 60, and then just let the pH rise on it's own.

    17,500 gallon IG Vinyl
    Pentair Tagelus TA60D Sand filter
    Pentair Challenger 1.5HP pump CFII N1 1.5A
    Taylor K-2006-A, Stenner 45MPHP10 auto chlorine feed

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