I used one for many months, then bought a second one to keep in a different grow space. I discovered that the new one read several hundred us/cm higher than the old one. I had been doubting some of my readings, as the same recipe gave lower and lower EC over time (and lower than the recipe stated). So I threw out the old one and bought a third one.
As soon as it arrived, I compared it to the second one - and again the third, newest one, read 300 us/cm higher than the second one!
They don’t have a calibration mechanism, so I don’t have an easy way to check them routinely. But they seem to degrade over time - the second one in only a few weeks.
I also bought an Apera meter, a bit more expensive ($50), but can be calibrated - however I found it impossible to calibrate without an error message, so I returned it.
Bluelab is my recommendation as well. Had mine for a few years. Never used Apera meters so can’t say anything there. My pH pen was out of calibration by 0.1 having never calibrated till more recently.
They have an all in one pen for 250 but I’m not a fan of AIO products.
Make sure to have storage solution and keep it topped off in the cap.
eBay truncheon by BlueLab.
Easy to use if you can work within 50ppm increments
Used $50 get it and scrub the sensors with Bartenders friend every once in awhile
They have knock offs now too. Been wanting to test one
