Apex Salinity reading

[H-TownMike]

I just bought a used Apex A2 a few weeks ago and I am still trying to get used to it, but I am getting strange readings. Does everyone's read like this or should it be more of a flat line? I wouldn't think the salinity would vary like this normally but again I am new to the Apex.

 

[Jamie814]

Readings always will vary slightly. Your graph shows only .3 ppt fluctuation which is nothing to worry about. It looks very consistent which could indicate a piece of equipment causing it, stray voltage or heater turning on and off.
If it starts wandering more than 1ppt it could be micro bubble accumulating on the probe tip. Shaking the probe in the water may also clear the tip of bubbles.