Installed a new cold water bladder tank . After flushing toilet the pump starts checked the tank it has no water in it. What would cause the tank to not take water. Could it be a weak pump. My pump is a jet pump 1/2 hp its about 25 years old

We get this question all the time. The answer is simple: Don't worry about it. A bladder tank is designed to have water below the bladder and air above it. When it is first installed, there is air both above AND below. The air below the bladder prevents the tank from filling as it is intended to do. However, that air will be dissolved into the water over the next several weeks and eventually the tank will fill properly. Just give it time.

Bang on jlisenbe! That gets you a greenie.
Hi antic-cat and welcome to The Plumbing Page at AskMeHelpDesk. This may help you to understand a bladder tank operation. Good luck, Tomn