I have a herpstat 2 and a ve 300 as well as a couple herpstat 1's. If you want to control 2 racks with one unit I'd go with the herpstat 2 as I've had absolutely no problems. There is also a herpstat 4 and a new herpstat 6 that can control 4 and 6 racks from one unit which would be the best bang for your buck. Spyder robotics also has a 10% off deal going on right now.