First question is what pex works best in concrete floors I planned to us 1/2 o2 barrier pipe? Next I've decided to try a waste oil burner to heat a tank of water. That water will be circulated through the floor in several zones (60x80 shop) and return to the tank. Hoping to have 500 gal tank. Thoughts or ideas I am totally new to this and am hoping to keep it simple?? Thanks