Justjoe
New member
Hey,
Its about that time I send out the:
"DON'T TRUST YOUR METER" reminder...
While most are trustworthy, even the good ones go bad.
I recently changed my kalk dosing routine and saw a quick climb in my pH, so I re adjusted my dosing. Something didn't seem right and my Salifert kit alerted me that my probe may not be completely honest with me, even though it would still calibrate well... so which one was lying to me?
Here is some interesting text from Craig Bingman on probe life, salt water and how they may interact over time:
"pH electrodes read high after long continuous duty in saltwater systems.
Replace the electrodes every six months or so. It isn't a problem with the meter, it is really an electrode issue. More precisely, it is an issue with old electrodes with a weak internal solution, and the salt concentration of the NIST standard calibration solutions. If the NIST solutions were a closer match to the salt concentration of seawater, this junction effect would be nulled out in the calibration process.
However, NIST calibration solutions are all you are likely to get on the market, so you just need to change out the electrodes every six months or so to get reasonable performance".
So new probe installed and it read closer to the pH test kit and all is fine. A new pH controller on my kalk dosing pump (to safeguard overdosing) will act as a second meter to watch over my reef tank pH.
Joe
Its about that time I send out the:
"DON'T TRUST YOUR METER" reminder...
While most are trustworthy, even the good ones go bad.
I recently changed my kalk dosing routine and saw a quick climb in my pH, so I re adjusted my dosing. Something didn't seem right and my Salifert kit alerted me that my probe may not be completely honest with me, even though it would still calibrate well... so which one was lying to me?
Here is some interesting text from Craig Bingman on probe life, salt water and how they may interact over time:
"pH electrodes read high after long continuous duty in saltwater systems.
Replace the electrodes every six months or so. It isn't a problem with the meter, it is really an electrode issue. More precisely, it is an issue with old electrodes with a weak internal solution, and the salt concentration of the NIST standard calibration solutions. If the NIST solutions were a closer match to the salt concentration of seawater, this junction effect would be nulled out in the calibration process.
However, NIST calibration solutions are all you are likely to get on the market, so you just need to change out the electrodes every six months or so to get reasonable performance".
So new probe installed and it read closer to the pH test kit and all is fine. A new pH controller on my kalk dosing pump (to safeguard overdosing) will act as a second meter to watch over my reef tank pH.
Joe
