Water chiller rdwc

OK I’m finally doing it I’m making my own rdwc hydroponics kit and my question is do i really need a water chiller. I’m gonna have a total of 5 reservoirs 4 for the plant’s and one main one but they will all be 7.5 gallon containers so i figured that each one when in operation should be about halfway full at about roughly 4 gallons per container at a total of 20 gallons would i need a water chiller for that i have a ac in the room to control room temp.