Confused Rookie (cF, EC, ppm)?
 

I've been trying to wrap my head around the whole nutrient world and just when I understand the concept I find endless arguments over whether cF, EC, or ppm should be used. Can anyone tell me what the fundamental differences are and how that applys to nutrient loads? ppm seems straight forward, but EC and cF are still a bit of a mystery...

I saw this post before, but didn't have time to reply to it then, and just plain forgot about it since.


Anyhow fundamentally they all use the same principal to measure the mineral content of the water. It's after that it can be confusing. All EC/cF/TDS/PPM meters start by metering the Electro-Conductivity (EC). From there it depends on the meter how they translate the readings. cF is basically the same exact thing but eliminates the decimal point. See a cF-EC comparison here: Fruit Requirements. TDS (total dissolved solids/salts) and PPM (parts per million) both convert the EC (Electro-Conductivity) into other numbers. Either way they need a conversion rate in order to do that. Most conversion charts/rates are built into the meters memory, but some you can change. Each manufacture and region where the meter was made has a different conversion rate, so comparing readings without knowing the conversion rate is unreliable. In other words, even though your meter reads 600 PPM, and someone eleses meter reads 600 PPM, the true values will be different unless both meters are using the same conversion rate to convert EC (electro-conductivity) into PPM (parts per million). If you want to use a meter, get a EC meter. There are no conversions to worry about, and not many people use cF meters.


Personally I don't use any EC/TDS/cF/PPM meters at all. Not even a pH meter. Well not a electric/battery operated pH meter. The inexpensive pH drops I use are much more reliable than any meter.

Thank you very much!