Can I use a Polypropylene Solar hot water storage tank for the storage of hot water from my boiler? They have a hot water maximum temperature of 200 degrees. 265 gallons is 994.50. Expensive. Cheaper than a 200 gallon thermal tank at $2000. Can insulate myself or have them insulate it. Unfortunately I would not have the higher temp capability of what a used propane tank could handle. How high of heat can a propane tank handle? Thanks for your time guys. No fire needed tonight. I think spring might be here. I suppose I could always protect it with a mixing valve like I did for the heat going into my radiant heat in the garage floor. Right? What do you guys think?