Mike Patterson answered 5/29/2011 Does A Pool Heater Need A Larger Propane Tank? Our Propane Guy Suggests That Our 100lb Tank Will Not Supply Enough Propane Gas To Feed The Heater Properly And Recommends A 320lb. Can I rig my natural gas water heater to burn propane from something like those Rhino tanks? Take out a nipple from the drip leg,for instance, and screw in some kind of hose that attaches to a small propane tank?