Extreme EC readings with new EC pen
I received my EC pen today, and after checking my solution, the pen read 10.00 ms/cm. I then tested my water and found it to be somewhere between .60 to .70. Can anybody explain why my nutrient solution is reading this way? I'm using GH Maxigrow and I am mixing a lot less than what they recommend. I've been using this strength for about a week now, and my plans appear to be doing better than when I had it at half this strength. Is this a water problem? A EC pen calibration problem (factory calibrated)? Help!