In order to fill a tank, we require that it have been hydrostatically tested within the last 5 years, visually inspected with the last year, have a working valve, and no visual damage. For your safety and ours, any suspect tanks will require testing regardless of their last test dates. We do not over-pressurize tanks, regardless of ratings. We will only fill to the working pressure of the tank plus 200 psi to allow for cooling. Our max fill pressure is 3600 psi for high-pressure steel tanks.