I have been using a hidrofarm thermostat I bought on ebay two years ago and I was very happy with it until it crashed on me two days ago. I had to buy a Helix cause i was not able to find Herpstat (I live in Mexico so it is hard to find good stuff). That being said, i'm very happy with it. Is very easy to use an set up and is giving me exact temperature.
Here's a photo of my rack. I use a modified home depot rack (yes, I took the idea from the youtube video) and 11" flexwatt for heat.
http://img.tapatalk.com/d/13/11/15/saqa5enu.jpg
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