[NewellCrazy]

you can tell diesel by the smell. If it doesn't stink of diesel, its boiler fluid. The Aqua hot doesn't use standard anti-freeze, it uses a food safe type (called GRAS or Generally Recognized as Safe) at a concentration that will convey heat pretty well. If you are leaking boiler fluid. (The fluid expands as it heats), Check your radiator cap which allows accumulation of a few pounds pressure in the tank and that slight pressure probably found a leak that isn't there w/out the pressure.