Strange ORP readings

[iReefer12]

For past 2 weeks I’ve been getting some strange ORP readings.

Any ideas?

So far I’ve ruled out Water Auto Top off and faulty probe.

 

[iReefer12]

+ Between 30th to the 1st I placed the probe in a cup of tank water to see if the spikes continued and then could see if it was a bad probe. Graph is pretty stable in that period.

 

[Randy Holmes-Farley Verified Community Expert]

ORP depends on pH, which might be impacted by dosing as well as the daily light cycle. If you are not dosing and it swings up and down faster than the light cycle, that might be electrical interference.