Good point, man. Yeah. I am expecting about a half gallon a day right now, based on what has been happening since I changed the reservoir. I have four gallons of mixed nutes and a gallon of phed water, so will be covered if they start drinking fast this week. I will be watching for increased consumption, though, and can top off in the morning and evening if need be.
If there isn't anything I learned is to keep the water cool, clean, moving, bubbling, phed, ppmed, and at the right level, and it will help the plants withstand whatever is going on on top. The reservoir is top priority when I am here, and will make sure to bug my wife enough while I am gone. I actually think Shen likes taking care of them, though she won't admit it!