Is my EC meter bad or Something else is going on?

Calibrate and clean the meter and you will know for sure. Clean it with a TDS/EC meter cleaning solution and buy the calibration solution. Even the expensive ones need to be cleaned every so often or you will get weird results.

ec meter was most profitable investment from all equipment, my last one lasted 5 years. they cost 10-20, so to have a spare is not a bad idea even if yours is still ok. i saw not one video were water ec was way off from label stated , either consumer research, o maybe some grower did, forgot it, but it stayed in mind. i know it will be in hundreds or tenth, but for calibration or understanding - will be still off the real readings. tap water i have now is 150 water i had in my grow house was 70-100 ppm in winter and a bit higher in summer, like 120 max.

Last week and this week when I made the feed it read 2.1 EC. I had to top off my bucket to get it down to 1.6 and both times I used the same amount of water. I plan on getting calibration solutions to verify but is the meter bad or is something else is going on? Two known readings, distilled water and my tap water, remain the same. Is this an issue where the results are repeatable but not accurate? Test by recommended by fellow grower: Tap water ppm (0.5 factor) 552 Distilled water ppm 6 100 ml tap water + 100 ml distilled water = 264 ppm Sounds about right? (stated accuracy is +/-2%)