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Thread: Accidentally increased alkalinity too high

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    Accidentally increased alkalinity too high

    I normally test myself but took water to a pool supply store to do it for me.

    For my ~20K saltwater pebble tec pool (with 3 spillovers), here are their test results:

    CL = 0 (my SWG is not working yet. Think I need to acid wash it)
    Salt = 3300
    Ca Hardness = 170
    Cyanuric acid = 10
    T.Alk = 70
    ph = 8
    no metals or phosphates

    They recommended i add 8.5 lbs alkalinity up, wait 4 hrs, shock pool with chlorine, then 20 lbs hardness plus (24 hrs after alk), then 9 lbs conditioner.

    I accidentally added about 13 lbs alkalinity up (stupid, I know). I waited a few hours with the pump on and re-tested with my own kit in two places and got T.Alk of 140-150. I use a Taylor Complete K-2006 test kit (recently purchased).

    It has been raining like crazy today, with more to come, so I know that is working with me. I have turned on the waterfalls to aerate. Pool store said not to add muratic acid to correct the pH. Is that right? What I read here was to bring ph down to 7.2 and aerate. Or would you not even be concerned about the alk being 140-150?

    Thank you

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    Patrick_B's Avatar
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    Re: Accidentally increased alkalinity too high

    Welcome to TFP!

    This is why we like testing our own with a reliable, good quality kit, and adjusting on our own but no worries, you can get this lined out.

    TA 150 isn't the worst thing and don't worry, it will come down. They are wrong on pH though. While 8 isn't the worst thing either, it will soon be higher with that TA. I would want it lower, perhaps 7.8 max, but if you want to start working down the TA, yes, lower to 7.2 and keep on with aeration and more additions until you get it lowered. It may take a little while. Do you have a good kit with fresh reagent?

    I would be concerned with no FC. Did they address that? If that were mine, I would get some liquid Chlorine/ bleach in there until my SWG was working. What's your water temp? It may be too low still for it to work well. And, is 3300 where you need to be with salt level for that SWG?
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    Re: Accidentally increased alkalinity too high

    Thank you for the reply.

    Yes, after perusing a few other posts/replies, I edited my initial post to show that I have a fresh Taylor Complete K-2006 test kit. I normally do all my testing myself, but got lazy today! My reason for getting it tested is that I've been working to get my salt back to normal, hoping that the SWG would kick on. Water temp is about 72-73 F. I'm not sure what is wrong with the Pentair IC40 that I have, but am going to do an acid wash when I have a chance, and see if that helps it kick into gear.

    When I goofed and added too much Alk, and later tested to find it at 140-150, I checked ph with my test kit and it maxes at 8.0, so I'm sure it is probably a bit higher than that now. With your advice, I will add some muriatic acid and will keep aerating.

    I bought some chlorine and will add a couple bags shortly as well. Should I hold off on adding the calcium hardness and cyanuric acid until I bring down the TA?

    Thanks again

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    Patrick_B's Avatar
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    Re: Accidentally increased alkalinity too high

    Are you sure of the Cya level at 10? Thats really 0 for all intents and purposes.

    I would not add much CH now, and probably wait until I knew the pH was at least as low as Mid 7s or a touch lower. Add it in small doses. To be clear, and before you add the CH, what are the bags of Chlorine made of?
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    Re: Accidentally increased alkalinity too high

    I've had a sock of CYA in my skimmer for several days. I'm a little surprised it is only 10. Just checked it and it is definitely <30, which is the lowest my kit goes.

    The CH is made of calcium hypochlorite.

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    Patrick_B's Avatar
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    Re: Accidentally increased alkalinity too high

    Ok,

    Just go with that for now. It will add some of the Calcium you need, and you can still adjust it later. As soon as all the Cya in a sock is totally gone, it wont take long before you can know where you are. Within a day of normal circulation for sure.
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    Re: Accidentally increased alkalinity too high

    The CYA is not dissolving very quickly. I probably had 6 or 8 lbs in a large tube sock, and it requires me squeezing it quite a bit to get it to dissolve. In similar situations in the past, I've had to take some pool water, heat it on the stove, add/stir in the CYA, and then dump it into the skimmer (once it cools a bit). Being low on CYA is routine after the winter months, but is a pain.

    So just to be sure, I will work to bring down the pH with muriatic acid, keep the aeration going, and add some chlorine slowly to bring that back into normal territory. Then I can add the calcium hardness?

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    Patrick_B's Avatar
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    Re: Accidentally increased alkalinity too high

    Yes, if you want to add the CH, but make sure the pH is down before/when you do. You might try putting the Sock in front of a return hanging from one of your brush poles or something. TFP suggests the sock because some people have backwashed it out of the filter, but I don't like fooling with it that way, and this is one reason. Give it lots and lots of squeezes if you want it to go faster.
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    Mod Squad Jimrahbe's Avatar
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    Re: Accidentally increased alkalinity too high

    D,

    Welcome to TFP... A Great resource for all pool owners that have been "Pool $tored"...

    You said " ...accidentally added about 13 lbs alkalinity up (stupid, I know). " No, that was not stupid, that was just a mistake. Stupid was going to the pool store in the first place...

    You say your SWCG is not working? What lights does it display? What is your indication of failure. With a water temperature of more than 70 degrees, it is not going to just spring back to life...

    Thanks for posting,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

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    Re: Accidentally increased alkalinity too high

    Only indication on the SWG I get is that the salt level LED stays red (low salt). Power to the cell is green, but under status, the cell LED is not on at all (neither green nor red). Flow is green, and sanitizer output is at 3 dots (~60%). I checked cell life and I think it is also at 60% if I read it correctly.

    Thank you

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    Mod Squad Jimrahbe's Avatar
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    Re: Accidentally increased alkalinity too high

    D,

    Well then either you don't have enough salt in your pool, or the IC40 is reading an inaccurate salt level. They are known to do that..

    So, you need to test to see approximately how much salt is in your pool. I use the Taylor K01766 salt test kit, but any salt test will work close enough for this test.

    If the salt is low on the test, then add the necessary amount of salt. If the salt is toward the high end of the range (2800 to 4500) then most likely the temperature sensor/flow sensor has gone bad. If not under warranty, it costs about $100 to get a new one and is a pretty simple DIY install.

    Thanks,

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP520 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2, added small 3 person Caldera Spa.

  12. Back To Top    #12

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    Re: Accidentally increased alkalinity too high

    Checked the salt with my SaltDip tool, and it reads 3,300, dead on with the pool store. It should be okay as the cell says ideal salt 3,400. It's not under warranty. Please share any info on the replacement sensor.

    I'm sure the pool store would have charged me for much more or suggested a replacement. Very happy with the help here!

  13. Back To Top    #13

    Re: Accidentally increased alkalinity too high

    Push and hold the "More" button for about 4 seconds and record what percent lights light up. Then press the "More" button again and record what lights light up.

    How old is the cell?

    What is the cell version number?
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    Mod Squad tim5055's Avatar
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    Re: Accidentally increased alkalinity too high

    I would recommend ignoring the TA for now and turn off the waterfalls. 140-150 TA is not the end of the world. It will cause pH to rise a little quicker, but nothing you can't handle.

    As you normally add acid to keep the pH in check it will slowly lower TA on it's own.

    Work on getting the salt/SWCG in line and add liquid chlorine until you get it going.

    Stop going to the pool store. They know less than you and will just take you off course.
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    Re: Accidentally increased alkalinity too high

    v2.01; says mfr date 7/26/10

    When I hold the "More" button down for 3-4 seconds, the LEDs for the % chlorination flash but it does not stop to show that any one LED is lit up. It goes right back to showing 3 LEDs reflecting 60%. I pressed "More" again right after doing this and all sanitizer output LEDs go dark while the Salt level, status and flow LEDs flash and then all LEDs go back to the way they were. Does this mean I need to replace the cell?

  16. Back To Top    #16

    Re: Accidentally increased alkalinity too high

    That's an old cell. The diagnostic I suggested won't work.

    Likely to be a bad temperature sensor. The white and green wires go to the temperature sensor. You could check ohms against a 10k chart.

    Based on the age of the cell, I wouldn't buy a new temperature/flow switch.

    Probably best to replace the cell.

    First check for scaling and clean if necessary.

    Then try increasing salinity to 3,800 ppm.

    If that doesn't work, probably time for a new cell.
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  17. Back To Top    #17

    Re: Accidentally increased alkalinity too high

    The temperature sensor is a 10k thermistor. Its resistance varies based on the temperature. The way it varies is known precisely. So the box measures resistance in ohms and calculates the temperature.

    If the thermistor fails in a way that’s obvious to the software, the software will ignore the thermistor and use 75 degrees F as the temperature.

    When using 75 as the default temperature, the salinity will be miscalculated by the software for any water temperature other than 75 F.

    The further the water temperature is from 75F, the more error there will be in the salinity calculation.

    If the thermistor drifts off calibration in a way that’s not obvious to the software, the software will use the incorrect temperature and the salinity will be off depending on how far the water temperature is from what the software thinks the temperature is.

    I suspect that the software is probably getting a temperature reading in the high 80s or 90s.

    One thing you could do is to cut the green and white wires. This should make the software use 75 F as the default temperature since it will lose contact with the sensor. This might make the cell work again.

    You could measure the resistance of the sensor by putting the test leads on the green and white wires going to the sensor. The resistance should match a 10k thermistor chart. For example.

    Temperature……….Ohms
    60……………………… 15,310
    70……………………… 11,882
    77…………………….. 10,000 (The 10K reference point)
    80…………………….… 9,297
    90......................7,333

    For example, if you measure the resistance as 7,333 ohms, the system thinks the temperature is 90F.

    However, if the water is only 65 F, then the system is going to calculate the salinity as much lower than actual.

    A light acid wash might help.

    Increasing the salinity to about 3,800 to 4,500 ppm might help.
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