I've never seen one before. Interesting. Thanks for posting. What's the situation that you're intending for it? Above ground waterline, or buried? You're in Tennessee... alot different than up here in Minnesota. I think it should probably work for you. His video shows it installed on a top float. Doubt that'd ever work up here... the float will just freeze into the water anyway.
Jobe valves has a full flow valve that you can mount below the waterline in the tank (i.e.: up through the bottom)
called the Topaz (
Amazon.com : Jobe Valves Topaz Valve with Detach Short Tail, 3/4", Yellow/Black : Garden & Outdoor), and it has a special port on it for inserting their "FrostPro" valve into (
Amazon.com : Jobe Valves Frost Pro Accessory, Yellow/Black : Garden & Outdoor).
The FrostPro won't fit into the MegaFlow valve though, even though it's a very similar valve design to the Topaz. Basically, you insert the FrostPro into the port on the Topaz valve, and when the weather gets cold, you open the FrostPro, and it'll let a small amount of water flow through the main valve and out the FrostPro. Yes, it'll overflow your tank, so you have to provide a drain away line, but it will keep your line and the valve from freezing. The FreezeMiser will overflow your tank too.
Next spring I'm planning on installing some of these Jobe Topaz valves on a shallow bury waterline (16" deep... we normally bury waterline a minimum of 6') to feed water stations out across the pasture. They will be used for watering all winter. I expect the only problem would be if the well quits working, then my shallow buried line might freeze. I'm planning on intentionally keeping good tall sod cover over the line through the winter, and then catching snow in that. I'll install the valve at the bottom of the tank, and let the "overflow" rise up right underneath the float... that should keep the float from freezing into the ice over the top of the tank. If the cattle want a drink they will push down on the float, just like the Mirafont or Ritchie "ball in the hole" energy free waterers. I'll attach an overflow line inlet on the float too, so if the water gets above the "float regulated height", it will run into the overflow, and I'll take that down through the water and out the bottom of the tank below grade, to a drain tile or a french drain or drainage ditch. Don't think I'll have too much trouble as long as I'm leaving some water running, even though we do normally get down to -20+ every year. Running a little water is less costly than heated waterers.