pH probe freshwater

[John Neuzil]

I have an X3 controlling my freshwater tank. I put in a pH probe and get a significantly higher reading than I should. Out of the tap our water is at 6.5. My tank through several other testing methods is 6.8 ish. The probe measures 7.8 ish. I tested the freshwater tank water with the system running my reef tank and get the same reading of 7.8. If I test my reef water with the freshwater system I get the correct reading, same as my reef. So the question is, is there something about the Hydros and pH in freshwater that I am missing? And yes the probe has been calibrated.

 

[Carlos]

I have an X3 controlling my freshwater tank. I put in a pH probe and get a significantly higher reading than I should. Out of the tap our water is at 6.5. My tank through several other testing methods is 6.8 ish. The probe measures 7.8 ish. I tested the freshwater tank water with the system running my reef tank and get the same reading of 7.8. If I test my reef water with the freshwater system I get the correct reading, same as my reef. So the question is, is there something about the Hydros and pH in freshwater that I am missing? And yes the probe has been calibrated.

Do the following:

1. Delete the input from HYDROS
2. Recreate the input but give it a DIFFERENT name
3. DO NOT calibrate the probe
4. Upload changes

What does it read now? HYDROS does not discriminate between salt and freshwater. The HYDROS gets the reading from the probe and displays it on the app. It is only showing what the probe tells it to show.

 

[John Neuzil]

Do the following:

1. Delete the input from HYDROS
2. Recreate the input but give it a DIFFERENT name
3. DO NOT calibrate the probe
4. Upload changes

What does it read now? HYDROS does not discriminate between salt and freshwater. The HYDROS gets the reading from the probe and displays it on the app. It is only showing what the probe tells it to show.

Now it reads 7.4. Should be between 6.5 and 6.8.

 

[Carlos]

How did you obtain the 6.5 and 6.8?

Try to calibrate the pump but only for 4.01 and 7.01. There is no need to calibrate at 10.01.

 

[John Neuzil]

I did the 7 and 4 calibration before I posted and no change. To get the values in the sixs I used a Hanna pH probe, aquarium Co op tests strips, off brand pH pen and a pH liquid test.

 

[Carlos]

Have you tried a different pH probe?

 

[John Neuzil]

Have you tried a different pH probe?

I tried testing the same water on two different systems so different probe and different Hydros. I guess Im beginning to question the other tests I ran. Having said that even my R/O DI water tests in the mid 7's with Hydros. Our TDS out of the tap is like 29.