I installed a new Flotec Bladder Tank. Luckly no leaks. I have set the tank to the specs of the pump... 20/40 (2 below) on... it ran great for a few minutes. thinking it was builing up pressure... But there is no water pressure. What am I missing? Help!

What kind of pump, submerged or above ground? If it's above ground, did you prime the pump?