@Nowlab it depends on what resin you used in the tank beforehand. A tank cannot be reprogrammed between regular resins and the more chemically aggressive resins (Tough 2000, Elastic, Rigid, and Grey Pro), though you can reprogram tanks within those two families to other resins within those families. The reason for this is that those resins wear out the tanks at very different rates (see https://support.formlabs.com/s/article/Maintaining-the-Resin-Tank-Form3?language=en_US#lifetime for tank lifetimes), so switching between them would mess up the calculated lifetime recommendations.