pinpoint moniter ques.

[1628mna]

hello,

i just recieved a brand new pinpoint ph monitor from marinedepotand after calibrating it and sticking it in my sump right by my topoff unit and in the same space as my return pump, the number on the moniter keeps jumping from7.9 to7.91 to 7.89 to 7.9(not in that exact order). did i calibrate it right or is this a result of faulty calibration?

where is the best place in tank to put the probe at in your sump?


thanx for the advice mike

[Hop]

If you put it in your overflow or tank, does the reading level off? You may have answered your own question when you said you put the probe right where your auto top off is located;)

I put my pH probe in the overflow.

[Randy Holmes-Farley]

from7.9 to7.91 to 7.89 to 7.9

Those are trivially small changes and are not a concern.

That said, one can get interference with the Pinpoint pH monitor from certain other electrical equipment, so if you get really whacko readings, or they jump around when lights are on (like big ballast mh lamps; jumping from 4 to 9 and back again), then you might run it on the battery or on a different outlet away from the lights.

These have more:

Measuring pH with a Meter
http://www.advancedaquarist.com/issues/feb2004/chem.htm

A Comparison of pH Calibration Buffers
http://reefkeeping.com/issues/2005-02/rhf/index.htm

[1628mna]

thanks for the info Randy Holmes-Farley . i didnt think that it really mattered i just wanted some reassurance. thanx for the links off to reading! randy does the location of the probe matter, i also thought that the water running past the probe in my sump would make it jump what do you think? i wanted to move it around last night but i thought just to leave it alone and let it settle down.


thanx again mike

[Randy Holmes-Farley]

In terms of the pH measurement, the location of the probe is fairly unimportant. pH may be a bit higher in a lit refugium or near limewater dripping, and lower near a CaCO3/CO2 outlet, but in general, most of the system will be about the same pH. Moving water should not impact a pH meter probe very much, but I would not normally put it in the most turbulent areas as bubbles on it might impact the readings.