ZOMG my pH is 8.65!! (Solved:bad calibration solution)

Discussion in 'Water Chemistry' started by exactlyobp, Apr 12, 2012.

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  1. RickM

    RickM Astrea Snail

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    Oh I understand now. I thought maybe there was something new I hadn't heard about. I prefer more natural levels myself although a lot of people seem to prefer elevated Mag levels. I just never heard of anyone recommending to raise Mg based on ca levels. My alk tends to be higher than NSW between 9-10 so I guess whatever works for each system
     
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  3. steve wright

    steve wright Super Moderator Staff Member

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    you got it

    part of the problem is the old precipitation situation
    you know the one, add cal and alk drops, add Alk and Calc drops
    many times that happens simply because the mag level could not support the targets for the other 2 ions in the solution
    so it became a more or less general term that your mag should be approx 3 x your calcium level and then balancing the Calc and Alk would be easier

    it does not have to be and it is not a certainty that you will suffer Calc and Alk swings if it is not
    but it is a relatively useful guideline IMO
     
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  4. RickM

    RickM Astrea Snail

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    I haven't really seen problems unless the Mag drops below 1000 or so. It really only became an issue with people who quit doing water changes. I remember when they first figured it out. I try to do weekly water changes so its never been an issue for me. And people swear chalices do better with higher than normal Mag levels but I haven't had any issue. Maybe once every six months I adjust Mag levels.
    The only real issue I know of that comes from high pH is that ca carb precipitates out faster.
    There is even some speculation that coral growth drives the pH up around coral reef by using up available co2. I remember coming across a paper on it when I was having that discussion with Calfo and doing some research on pH and reefs. If I remember correctly he was of the opinion that corals grew faster at a higher pH.
     
  5. exactlyobp

    exactlyobp Giant Squid

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    Ok Ive just tested for KH.
    It's 6.4dKH (2.3meq/l).
    [​IMG]
    I did water change (10 gallon) 3 days ago. Alk is not really catching up as I thought after all. Ever since I started this 90, the pH was always on the high side, I guess it's time to start dosing regularly? Sodium bicarbonate, instead of soda ash, correct?

    And the pH is up to 8.5 now.
    [​IMG]

    Thanks Rick for your input so far as well!! Im not as freaked out as yesterday :)
     
  6. exactlyobp

    exactlyobp Giant Squid

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  7. exactlyobp

    exactlyobp Giant Squid

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    Still rising. It's at 8.63 now :(
     
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  9. exactlyobp

    exactlyobp Giant Squid

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    It topped at 8.64 today.
    [​IMG]

    Ive read the article that Steve referred to and it said that "excessive pH is through high pH additives," in other words, there is no way that its this high without dosing? Thus the probe is bad??
     
  10. steve wright

    steve wright Super Moderator Staff Member

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    Or

    possibly the calibration fluids are suspect?
    because if they are out by 0.5 for example and you set the meter to 10 in a sample that is 9.5 when you add it to a real sample that was 10, it would read over 10

    so it may not be probe it may be a calibration solution issue
    RHF in his other article did show how far out some of these things can be
     
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  11. malac0da13

    malac0da13 Torch Coral

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    What does your probe read in pure RO/DI I can not think of a reason that your pH is that high with just water changes. I would definitely suspect bad calibration fluid or bad probe or something. Are you dipping the probe right into those bottle or pouring it into a container?
     
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  12. RickM

    RickM Astrea Snail

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    I can't think of anyway to get high pH without special buffers meant to raise it and since you aren't adding anything... I would write it off as bad probe or calibration and not even think about it. I don't check pH, my pH probe is in the ca reactor and it reads high. At 6.5 it was making the fluid too cloudy. I simply change the controls to compensate for bad reads.
    Make sure you stay on top of alk, it's the only thing I check often. Twice a week, once a month for ca, almost never check for Mg, po4, nitrates, pH unless I am having issues. Want those sps to grow, give them plenty of ca and alk.
     
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