Air/PPM questions

You use a ec or tds meter...ppm is parts per million.. you use it too tell how much of your nuriants are in the water after the plant has been drinking the water and eating the nutriants... ppm will go down if your plant eats more nutriants than it drinks water, and it will go up if it drinks more water than it eats...this helps you see if you are feeding your plants the right amount of nutriants..

the site oldsanclem listed will answer all your questions... the whole site is helpful..but this section on FAQ will give you a good answer on everything you want to know and it is nicely arranged in catagories and will most likely give you a better understanding than me

Sharp Rubber Duck (.NET) - Cannabis cultivation: Overgrow's GrowFAQ

before I go into the FAQ because I like one on one awnsers :)...where can I buy an ec meter? secondly how do you know how much to exactly feed your plant, does it vary?

ebay... i just picked up one..most are exspensive but the one i got on ebay is cheep and from what is said above these are just as nice for reading ppm..

HM Digital TDS-3 Meter w/Case, TDS3/Temp/Salt /Tester - eBay (item 370018437880 end time Feb-08-08 18:20:54 PST)

it changes according to how ur growing it, and what stage it is in... go to that site and it will tell you everything you could want to ask about them and more