ppm question

hi guys all the post i see people talkin about (ppm) douse that mean parts per million??
also i know its to do with the feed but i dont understand what it means because my e.c pen reads like 1.2 would that = 1200 ppm??

Thanks

depends on the scale that EC pen uses...different manufactures and different regions of the world use different scales:

USA 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
European 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Australian 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

For example,
Hanna, Milwaukee 1 ms/cm (EC 1.0 or CF 10) = 500 ppm
Eutech 1 ms/cm (EC 1.0 or CF 10) = 640 ppm
Truncheon 1 ms/cm (EC 1.0 or CF 10) = 700 ppm

So what brand EC pen do you have? Can you look at your manufacturers website and see what they use for a conversion?

Yes, it means parts per million. EC and ppm are different ways to measure the same thing. Here are some handy links:
http://www.4hydroponics.com/convertPPM.asp
http://www.gardenscure.com/420/hydroponics/96521-printable-ec-ppm-cf-conversion-chart.html