Difference between TDS and EC meters

Ok so i was doing some reading about TDS. How its calculated, its accuracy and so on. Well while i was doing my research to better understand how TDS works and i came across this article online. For anyone confused about TDS or EC go to the web address below. good info!

http://www.hydroponics.net/learn/debate_over_ec_and_tds.asp

Greentree hydro rocks, they are the inventors of the O.G ebb and flow system.

hell yea i just figured I'd post that since everyones always asking questions about TDS, PPM, EC and so on! Thanks for stopping in