I built a nutrient reservoir, auto watering, drain to bucket system. Everything works great! Only issue is that, I can’t keep the temp in the reservoir down between 65 - 70 degrees. This is causing the PH to change too. Since I use Advanced Nutrients Perfect PH for coco, this PH change has become a problem as well. My 2 stir pumps are the cause for this temp change. They raise the temp! But, I need my nutes to stay mixed very well together. My effort to control the temp started out with small frozen water bottles. I have now started to use the 1 gallon water jugs, frozen hard as a rock. I even bought an inexpensive transmission cooler from Amazon. Set that up to have the nutrients pumped through it with a 120mm fan blowing on it. Didn’t work. This is a real PITA!
To those that have a reservoir . . . . . what cooling system have you designed/made that works??