pH calibrate question

[vincent843]

So, I calibrated my probe 1st time today after the first set up 8 month ago. Before calibration, the probe read tank pH at 8.23.
When inserted the probe to fluids pH 7, and 10 the probe read 7.83 and 10.93. After selected these 2 set points, put probe back to tank, the probe read 7.99. So .24 different between before and after. Is this normal?

[kenargo]

Yes, it could be; when you put the probe back into the calibration fluids (after calibration) did it read correct? After calibrating you should 'test' the calibration by placing the probe into each solution and it should read accurate; if it does you can be assured the readings using the probe will be accurate.

Note: the reading during calibration are meaningless; they are only needed to tell when the probe has settled.

[vincent843]

Did not re-check at 7, but at 10 it read 9.99.

[kenargo]

It sounds like the probe is calibrated then and the reading in the tank you are getting now is correct; the old reading, without the probe being calibrated should be ignored.

BTW; 7.99 tank PH is not bad,I mention this because I've seen many tank owners get bogged down on PH and think it myst be perfect (8.3-8.4) when actually this is not true. When parameters are correct (Alk mostly wrt PH) then the tank will reach a natural PH (natural for itself + inhabitance + environment (house)).

[vincent843]

Thanks.

[vincent843]

I don;t know what 's going on, but dipping the probe in vinegar and recalibrate has something wrong, now my system read only, 7.8, which turn off my cal reactor.

[vincent843]

Put the probe in test solution, it read 6.99 and 9.99. while salifer read <7.8 but API read 7.8. So all the times, for the past 8 months the probe been gave me the wrong info,

[kenargo]

<a href=showthread.php?s=&postid=14765330#post14765330 target=_blank>Originally posted</a> by vincent843
Put the probe in test solution, it read 6.99 and 9.99. while salifer read <7.8 but API read 7.8. So all the times, for the past 8 months the probe been gave me the wrong info,

Yes, if you did not calibrate the new probe when you received it then it would have been incorrect. Now that it is calibrated you should get accurate readings.