pH meter or Salifert is more reliable.

[Osama]

I calibrated my pH probe and I still get a significant difference in readings obtained from Salifert test and from the probe. The probe is two years old. Rdg from the probe were 8.4 from Salifert 8.1 .. I relied on my probe for 2 years but my pH is creeping up.... What do you think/suggest. Your thoughts are appreciated

 

[Marcosreef]

Osama,

You should probably get a new probe for your meter. They reccomend changing them out every 18 months (Pinpoint).

I'm not familiar with the Salifert pH test kit, so can't say about the accuracy.

Either way, a properly calibrated pH meter is better than a test kit. (IMO)

Regards, Marco

 

[slojmn1]

I'd have to agree with Marco about getting a new probe. I am also due for a new probe on my Ph monitor. I think one way to tell if they are going south is by how difficult it is to get them calibrated. Mine is starting to get more difficult to calibrate and I am at the 14 month mark so I figure it is starting to go.

 

[Osama]

Marco & Slojmn1 Thanks for the response.
Slojmn1; What do you mean when you say it is very difficult to calibrate? Mine is hookedup to a Neptune system that takes the readings for the pH fluids and adjusts the readings to compensate for difference..

 

[slojmn1]

I was speaking of my Pinpoint pH monitor and probe. I am not familiar with the Neptune system and how it works with a pH monitor. With the Pinpoint you need to calibrate using calibration fluids. As the probe gets older the calibration reading fluctuates between numbers more readily and it is more difficult to get it to stay at 7.0 or 10.0 during the calibration. It will bounce around the number driving you carazy .