Temp effect PH ?
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Randy Holmes-Farley
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That temp change won't cause an important change in pH in a reef aquarium. 
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Z06-Hec
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I have a Seneye Reef monitoring my 150gal. I am pretty sure the temp readings are off as I have tested with another digital thermometer and there is a a difference of 5 degrees or so.
Anyway according to the Seneye when my temp swings up and down my PH is swinging as well.
so whenever this happens my PH is going from 8.2X down to 7.8x then back up etc...
Anyway according to the Seneye when my temp swings up and down my PH is swinging as well.
so whenever this happens my PH is going from 8.2X down to 7.8x then back up etc...
Randy Holmes-Farley
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If you are seeing daily pH swings, that is due to photosynthesis using CO2 during the day (raising pH) and respiration producing CO2 during the night (lowering pH). Daily temperature swings follow the same profile due to heat from the lighting, but it is not the temperature that is impacting the pH. They are both caused by the light cycle.
There is a small effect of temperature on pH. Over a few degrees it is not that significant. I address it in this article section:
Temperature Effects on pH Measurement
There are two different ways that temperature impacts pH measurement. The first involves actual chemical changes in the solution that you are measuring. Acids can, for example, become stronger or weaker as the temperature is changed. This is how calibration standards change their pH as a function of temperature (which is discussed in more detail in the calibration section below). If the solution has solids in contact with it (as is the case with saturated limewater in the presence of excess solids), the temperature can also impact how much acid or base is in solution impacting pH, and how much is just solid sitting on the bottom of the container. These effects are specific for every solution that you will encounter, and there is nothing general that one can or should do about this, except be aware that it happens.
The second impact of temperature is on the pH electrode itself. pH electrodes change their response in a very clear way as temperature is changes. They respond more strongly to pH changes at higher temperature than at lower ones. At 100 ºC, they change their output potential by 74 mV/pH unit, and at 0 ºC, they change by 54 mv/pH unit. Because pH meters are typically standardized at pH 7 (that is, zero mv = pH 7), the error from temperature differences gets greater and greater as the pH being measured gets further from 7. So it may be trivial when measuring something with a pH of 7.1, but very important when measuring something with a pH of 10 (or when calibrating with a pH 10 buffer).
There are usually three different ways of taking temperature into account. One is to make measurements close to the temperature at which you calibrated the meter (say, within a few degrees). The second is to "tell' the meter what the temperature is (digitally or with a dial). The third is that some meters have a temperature probe, usually called an ATC, which you stick into the measuring solution. This probe reports the temperature back to the meter, and the meter makes any necessary corrections (for this type of temperature effect).
As long as you use one of these three ways of dealing with temperature issues, you will get reasonably accurate readings.
There is a small effect of temperature on pH. Over a few degrees it is not that significant. I address it in this article section:
Temperature Effects on pH Measurement
There are two different ways that temperature impacts pH measurement. The first involves actual chemical changes in the solution that you are measuring. Acids can, for example, become stronger or weaker as the temperature is changed. This is how calibration standards change their pH as a function of temperature (which is discussed in more detail in the calibration section below). If the solution has solids in contact with it (as is the case with saturated limewater in the presence of excess solids), the temperature can also impact how much acid or base is in solution impacting pH, and how much is just solid sitting on the bottom of the container. These effects are specific for every solution that you will encounter, and there is nothing general that one can or should do about this, except be aware that it happens.
The second impact of temperature is on the pH electrode itself. pH electrodes change their response in a very clear way as temperature is changes. They respond more strongly to pH changes at higher temperature than at lower ones. At 100 ºC, they change their output potential by 74 mV/pH unit, and at 0 ºC, they change by 54 mv/pH unit. Because pH meters are typically standardized at pH 7 (that is, zero mv = pH 7), the error from temperature differences gets greater and greater as the pH being measured gets further from 7. So it may be trivial when measuring something with a pH of 7.1, but very important when measuring something with a pH of 10 (or when calibrating with a pH 10 buffer).
There are usually three different ways of taking temperature into account. One is to make measurements close to the temperature at which you calibrated the meter (say, within a few degrees). The second is to "tell' the meter what the temperature is (digitally or with a dial). The third is that some meters have a temperature probe, usually called an ATC, which you stick into the measuring solution. This probe reports the temperature back to the meter, and the meter makes any necessary corrections (for this type of temperature effect).
As long as you use one of these three ways of dealing with temperature issues, you will get reasonably accurate readings.
