No, Temperature and Humidity are controlled via a bank of fans. Ten in total, which are turned on via one of the relays.
The total amps for the fans is about 8A. And this includes the spike when the fans are turned on.
The control for the fans isn't picture perfect, but will be rewritten when I have the time for it. The problem with the temp/humid control is that there's no hysteria, so if the temp/humid swings around the setpoint the relays will turn on/off quite fast and then there's a chance that they burn out...
More detailed instructions then already provided will not be made. I think that the provided information should be enough to build one yourself. I've included the schematics for all the sensors, where I bought them and provided the code... The rest, how you actually solder the parts you can find out for yourself...just ask Google and it will provide...
The most difficult thing was writing the pH control algorithm, since I'm not a programmer. And that's provided in the beginning of the post 
I might be persuaded to build one for you, but that's gonna cost you... 
Hey...isn't figuring out these things not part of the fun in playing with Arduino???
Don't forget...Have fun and if you run into trouble while building one, just ask your question here and I will try to answer you as good as I can...