I've noticed that the water pump and electronics at the base of the water reservoir heat up the water significantly. It's been a huge problem for me. I've had a fan blowing on the reservoir in order to keep air flowing across and below the base in order to keep the water cooler. It's a far from optimal solution, but it does the trick. I'm disappointed in the AG solely due of this. This definitely limits my grow and my enjoyment of the growing process. I'd appreciate others' input on the matter who have to deal with similar issues.