This will be my third Neptune Systems branded double junction salinity probe in about two years. The first one came with my original Apex and worked acceptably well for about a year, then started giving super low readings despite careful calibration. The second probe replaced the first, and it too was unable to return meaningful data out of the box.
To rule out the port being bad on the Apex unit I purchased a PM2 module, and it didn’t improve the situation at all. I even plugged one into the Apex, one into the PM2, calibrated both, and to my disappointment neither probe was within 10 points of one another and neither was correct.
Fast forward a year, and new tank, new Apex EL, and new probe connected via the PM2. Tank salinity verified using refractometer and Hanna HI98319 as 34.5. What does the probe say, brand new out of the box? 10.1!
Calibrated, reverified tank measure, and still nothing.
I love my Apex(es) and my many modules, CORs, DOS, etc. Would recommend them to anyone.
After spending a ton of money on two new probes, a PM2, and quite a few calibration pouches I am about to declare that the salinity probes are completely worthless.
Caveat Emptor
To rule out the port being bad on the Apex unit I purchased a PM2 module, and it didn’t improve the situation at all. I even plugged one into the Apex, one into the PM2, calibrated both, and to my disappointment neither probe was within 10 points of one another and neither was correct.
Fast forward a year, and new tank, new Apex EL, and new probe connected via the PM2. Tank salinity verified using refractometer and Hanna HI98319 as 34.5. What does the probe say, brand new out of the box? 10.1!
Calibrated, reverified tank measure, and still nothing.
I love my Apex(es) and my many modules, CORs, DOS, etc. Would recommend them to anyone.
After spending a ton of money on two new probes, a PM2, and quite a few calibration pouches I am about to declare that the salinity probes are completely worthless.
Caveat Emptor