Let The Sun Heat Your Stock Tank
By: Grant Pound, Snowcliff Ranch.
Water is always the limiting factor here in the west. Access to water determines where I put my fences and defines my pastures. In the winter, it’s even tougher. The ditch is dry and the creek is often frozen. I have places I would like to put yaks, but water has to be hauled and it, too, freezes.
I tried a battery powered tank heater with a solar trickle charger that did not work. The battery was probably too small and the trickle of electricity too weak to keep up with heating a 70 gallon stock tank.
Since then I have broken a lot of ice. Each ice breaking event makes me think there has got to be a better way. I asked a lot of people what they did and found a lot of home remedies for ice-filled stock tanks, and decided to build a passive solar tank.
I found an article in Mother Earth News that showed how to insulate a stock tank. I took that as my starting point. I decided I would build my tank with only materials I had on hand. The tank I had to buy as well as a couple of cheap yoga mats and three tubes of silicon caulk.
The basic elements include a 6’ x 2’ x 1’ metal tank with one side painted black. It holds about 70 gallons. I wanted one that wasn’t very high so calves could drink out of it. The rest is the outside structure, insulation, windows for heat gain, black PE pipes for warming the water, and a lid that reduces the surface area.
I built a box that the tank would fit in using 2×4’s. This gave me room for 3.5 inches of insulation on three sides and the bottom. I added two supports along the long edges because of the high probablility that yak calves would stand on the box. I cut the insulation to fit between the supports and caulked around the edges. On the side that would face south I painted it black. I then cut a bunch of 3’ PE black tubing I had from another project into lengths that would fit upright along the front of the box. I positioned these with no space in-between and caulked them into place.
Scrap plywood was attached to three sides and the bottom. I primed and painted the exterior surfaces and caulked all the joints. I put three layers of paint on since this box would probably get treated pretty roughly by the yaks. The box now looked like a coffin and we started referring to it as the sarcophagus. On the south side, I attached clear plastic sheeting left over from the green house.
The top was made of two pieces of plywood with yoga mats for insulation. I cut a hole for drinking that was about the size of three buckets overlapped. The other end I cut a square window and covered that with the same plastic as the south facing side.
Finally, I put two runners on the bottom made of 2x4s so I could drag the sarcophagus if I had to.
How did it work? Let’s say I am glad I built it, and glad I did not spend a fortune on it. At 18° F overnight there is a slight slush on the surface of the water. At 2° F overnight, there is about .5 inch of ice that has to be broken. If the sun doesn’t come out all day, it will freeze up to an inch at 20° F. The calves do get up on it, but I positioned it with the top window outside of the enclosure. It was well worth building, but does not eliminate ice breaking entirely. It works best if the tank is kept fairly full.
This construction could be used with any sized tank. However, the wood, insulation, runners and top add several inches to the height of the tank. Some of my stock tanks are already almost too high for yaks and I didn’t think they would be able to drink if I used those tanks in this project. Starting with a tank that is no higher than 24” would probably be fine.
What has worked for you? Please feel free to add your solution in the comments. If you would like to write a blog about a different solution, I’d be happy to post it here.