i dont check temps man but im sure its around 70 degrees, i wouldent worry so much about that as to worrying about light leaking in the rez, organic matter in the rez, or not enough air in the rez. People love to hate on H2O2 but every single time i have the beginning stages of root rot i use it and within a few days it clears right up, i have had to use it 4 times this grow so you definately should pick some of that up. its a must in my opinion. if you are worried about temps though just check them and put some frozen bottles in there daily but like i said i dont worry about temps because liquid is normally between 5 to 10 degrees cooler than ambient room temperature if the liquid is in a sealed container IE the rez and my temps are normally at 73.