PPM, TDS, EC & Nectar for the Gods with Dutchman420

So if you have been following along we did a slurry test and to do that you need a ppm meter or a tds meter...maybe a truncheon meter?..whats the difference?..how do i know what reading to use?...What is the difference in my meter from others?...what is ec? how do i know which to use? let me try and explain this to you...it is kindof tricky so grab a pencil and take notes....