Maybe don't beat around the bush and post some pics of said measurement or the brand name.
Could be your EC meter is off, or that your tap is spitting out madd minerals or the container was dirty. Might want to test it using a calibration solution.
also maybe your measurement is off on the fertilizer or it was not mixed up? so many knowens.
Best to try and troubleshoot then find a solution. also some EC pens record in different numbers. This can help solve that problem.
https://www.translatorscafe.com/unit-converter/en-US/electric-conductivity/14-12/electrical%20conductivity%20unit-microsiemens/meter/