I have only seen one solar water heater, used for horses. It worked OK. Downsides were it did not hold a lot of water, like 20 gallons. Good for one horse, not for multiples. It has a floating ball cover, which got frozen when horse dripped on it. Some vegtable oil is supposed to help prevent the freezing problem. It also was pretty expensive for a plastic unit. The person who owned it, was satisfied, only had one horse. Another idea to consider would be a propane water tank heater. Also rather expensive, but appears to be a well thought out idea in several designs. Do a search for sellers. Lots of cattle and sheep owners who pasture animals where there is no electric available. Those who owned them were pretty happy with the heaters. You could resell it when you didn't need it anymore, probably get most of your money back. Not sure how fast heaters go thru fuel. The livestock owners did protect the fuel tank and heater unit, so animals could not reach or rub against it. Cows are so ready to break things rubbing on them, that good protection would be important!! We insulate our tanks inside wooden boxes. This does hold in the heat, keeps water from freezing quickly. We have electric heaters, so it saves us money not running heaters all the time.

As long as the Fuel is flowing there is not an Issue ! Just like Water in a Pond without flow , the Impurities Settle out and cause restriction to Normal Flow ! Note: The Solution of Pollution is Dillution...Thus Fuel Additives Bloke ! P.S. Use It or Lose It ! As We Say North of the Border ! :).

Okay, I've lived in the South for almost 40 years and the only kudzoo I know is that awful stuff that drapes over trees and kills them. I know that when it was originally brought to this county it was supposed to be used for cattle fodder and Southerners have been sorry ever since! Can this be the same thing? Some good purpose for this awful plant? Tell me more!

This won't help the OP, but for others planning a bath remodel, I'll make a recommendation for the brand we used. We used the Jaclo handheld/grab bar combo. The bar and the attchment are made of metal, solid and well made, and can be adjusted to any position and tightened to stay in that spot. No droopy handhelds!