Why can't I use a 25mS fluid to calibrate my conductivityprobe?

[mdanielse]

For a brackish aquarium setup I don't want to use the standard 50mS fluid for the conductivity calibration but a 25mS.
But the Profilux does not allow this, I can not select a calibrationvalue below 40 mS.
How can I tackle this problem:confused:

Greetings,
Jack

[GHL Support]

Sorry, then the minimum has been limited by the software to 40 mS (25mS was not considered because this is rather unusual to be used).

[mdanielse]

If it is only a "simple software problem" with not to much impact on the overall programming it would be nice to change it in a next firmware/software release. So that people who have a brackish aquarium(with lower salinity levels) can calibrate there conductivityprobes more accurate than in the current situation.

Something to punt on your (probably very big:o) To-Do-List..............




Sorry, then the minimum has been limited by the software to 40 mS (25mS was not considered because this is rather unusual to be used).

[Gunther]

If it is only a "simple software problem"
It is not. There is an electrical signal from the probe. This signal is measured and transformed into the conductivity value by using the ADC value fixed by calibration. So if you use - with same electronic - a lower calibration point, the ADC value also will be lower. Combining half the electronic signal with half ADC value will result the same value at the end (in fact, it´s less accurate due rounding errors are bigger for lower values), so at the end of the day you will win absolutely nothing (no better resolution, not more accuracy).