You appear to be confusing two standards, EC & PPM. 700 is a ppm number. To convert EC to ppm you need to multiply the EC by a factor (I think it is 500 - but I'm not totally sure that's the right factor). So, .66x500 = 330ppm.

Do like Ga Grown said - Google your meter and read the manual and find out what the correct conversion factor is.

PC :smokin: