Problem measuring EC. Is it my measuring device? Or maybe my measuring method? Im very confused. Help please!!

Приветствую, бро! проверьте свой прибор на минеральной воде из аптеки! В аптеках продается вода с точным значением присутствующих солей! Так ты определишь врёт твой прибор или нет! 👌😇👍 Удачи, дружище! 👋

just try to check water from the supermarket it should be 0.2 to 0.5 i think your ec meter working bad because the plant doesn't look like it's being watered like this

i would guess it's the callibration of your EC meter. I think the 3.5-4.5 range would cause some major issues well above and beyond anything i see in your recent week of diary. some yellow at bottom? perfectly normal in many cases in flowering period. check instructions for callibrating it, if possible. find something with a known EC and measure it (RO water would be very low from a good RO system), if you can't callibrate.