Guys - it has been long time, but Growduino V2 is ready! See this
And if You want, You can see my project Growduino V2 - it's finished and can be manufactured!
After several years of development, Growduino V2 appears, a new and much more sophisticated version of the device for both manual and automatic, local and remote climate control and device control in closed cultivation environments. It measures everything from temperature and humidity, through water level and water temperature up to light intensity, EC, pH and CO2. It allows you to set up countless amounts of parameters, control lights, ventilation, humidification, irrigation, but also less traditional heating and refill the water, room heating, dehumidification and last but not least, CO2 dosing. Everything is in the graphs in the browser, you can watch and control your growroom from the other end of the world, even over your phone or tablet. By email you receive notifications when something is wrong, no standard device allows this. Growduino V2, of course, has SSL secure communication, you are logged in with the password, no one else gets to your device. Plus mega cool feature! A webcam to help you see what happens in the growroom day and night.