You gotta give ppl a chance to reply,answers are not always instantaneous...ppl have lives...

Anyway,i use a truncheon pen and it has worked witout fail for the past 3 years.
Quick and precise but the price might throw you off,depending on how big a grow you actualy have. :jointsmile:

you can have a look at it here: Bluelab Truncheon Meter - EC, CF and ppm measurements

QB