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Thread: Having trouble interpreting pH results today

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    Having trouble interpreting pH results today

    I never had issues with figuring out our pH using the basic OTO test kit for pH and chlorine. Well, today, I am having a major issue determining what our pH is as I have never seen this color before. Yesterday, our pH was fine and is usually somewhere around 7.6 or so, but today, it is a more red color, and I can't tell if it is darker than 7.8, or lighter than 7.8 and somewhere in between 7.5 and 7.8. Anyone run into this before? Tried taking pics to show you guys but the pics do not come out good enough as to where you can tell the exact color.

    What would a reddish color indicate? I'm assuming it goes from that brownish-pinkish tone at 7.5 to a more reddish color (between 7.5 and 7.8) and then to the purplish color at 7.8 and beyond, is that correct?
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

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    Richard320's Avatar
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    Re: Having trouble interpreting pH results today

    High FC can do weird things to the pH test. It reacts with the red stuff and makes it go purplish.

    Dump it out and try it again.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
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    Re: Having trouble interpreting pH results today

    Quote Originally Posted by Richard320 View Post
    High FC can do weird things to the pH test. It reacts with the red stuff and makes it go purplish.

    Dump it out and try it again.
    Hi Richard,

    Our FC is only at 4. I tested again three more times and same color, that reddish color. I am guessing it is closest to 7.8. Not sure.

    At this point with a pH climbing up higher over time, and a TA of only 70, would it be ok to add some acid to bring down pH a bit with that low TA? Or should I leave pH be for now?
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

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    Mod Squad jblizzle's Avatar
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    Re: Having trouble interpreting pH results today

    If the pH test looks red, then it most likely is too high and you need to add acid to lower it. You never mentioned a TA value.
    Jason, TFP Moderator
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    Re: Having trouble interpreting pH results today

    Quote Originally Posted by jblizzle View Post
    If the pH test looks red, then it most likely is too high and you need to add acid to lower it. You never mentioned a TA value.
    TA of 70, which I mentioned above. How did it jump from yesterday to being okay to way too high today? I check it daily.

    So, when you say too high, what number? I have no clue what number to use when calculating how much acid to put in. It is not as dark/purple as 8.2, but seems closer to 7.8, but not even in the "purple" shade family, so I have no clue what I am dealing with.

    Also, my TA a bit on the low side. How much will the acid affect that?
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

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    Mod Squad jblizzle's Avatar
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    Re: Having trouble interpreting pH results today

    OH, that TA is fine.

    You are looking at the colors not me. Try one fewer drops or one extra drop and see if that helps you match colors.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Having trouble interpreting pH results today

    Quote Originally Posted by jblizzle View Post
    OH, that TA is fine.

    You are looking at the colors not me. Try one fewer drops or one extra drop and see if that helps you match colors.
    Thank you. That was helpful. For some reason, when I added four drops first, and then added a fifth drop a second or two later, it came out more purplish, closest to 7.8

    Would you add acid with a pH of 7.8, and a TA of 70 at this point? If so, what would you want the pH to come down to? We're getting ready to swim now so I would probably add the acid later on or tomorrow.
    7+ years, inground, 25,000 gallon, vinyl, sand filter.

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    Mod Squad jblizzle's Avatar
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    Re: Having trouble interpreting pH results today

    As long as it is in the 7s you are fine.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
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    Richard320's Avatar
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    Re: Having trouble interpreting pH results today

    Quote Originally Posted by suziequsie2945 View Post
    Thank you. That was helpful. For some reason, when I added four drops first, and then added a fifth drop a second or two later, it came out more purplish, closest to 7.8

    Would you add acid with a pH of 7.8, and a TA of 70 at this point? If so, what would you want the pH to come down to? We're getting ready to swim now so I would probably add the acid later on or tomorrow.
    Plug your numbers into poolmath and target 7.4 pH. Dribble the acid in front of the return and maybe make a couple passes in the area with the brush to get it to disperse, and go ahead and get in. You'll mix it faster than the pump alone will.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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