We recommend inflating your board between 15-22psi. For heavier riders we recommend aiming for 18-22psi and for lighter riders we suggest 15-18psi. If you're unsure, aim for 18psi or until you can no longer push down on the pump (with your arms locked and knees bent) as this means your board will provide the perfect stiffness for your weight. It is also worth considering the type of paddling conditions on the day. If the conditions are choppy, you're taking a passenger or you are playing in some surf, we recommend adding a little more air.
It is impossible to over inflate your board using a Titan hand pump so you could keep pumping all day long but once you hit 22+psi you have hit the maximum stiffness for the board so will simply burn up valuable energy that you could be using on the water.