Here's some really cool stuff I found:

Hydroponics Calculators

Calculate light requirement, CO2 requirements, air exchange requirements, ppm, and others, and learn what's wrong with your plants. Shows different hydro systems too.
Opie Yutts Reviewed by Opie Yutts on . Calculators and plant problem charts Here's some really cool stuff I found: Hydroponics Calculators Calculate light requirement, CO2 requirements, air exchange requirements, ppm, and others, and learn what's wrong with your plants. Shows different hydro systems too. Rating: 5