Our house is built in the year 2000. We have a well system and lately our pressure drops when we use it. For a second, water trickles down and then stops until the pressure is back again. This is happening for a few months. Do you know what is wrong with it? We have a Well-X-troll tank by Amtrol and the normal pressure is about 55 psi. The model number is WX - 252

I moved your post. It didn't belong tacked on to another question. You're going to hafta check your bladder tank and after that, if the tank's OK, the check valve.
Let me explain the function of a bladder tank. Pressure and bladder tanks provide a air cushion that produces water pressure in your system so your pump doesn't kick on every time you draw a glass of water. A bladder tank has a neoprene membrane in the center. As the pump puts water into the bottom half of the bladder tank the membrane compresses the air in the top half. When the pressure reaches the cut off point in the control box the pump shuts down. However you still have between 40 to 50 pounds of pressure pushing the water out to your system. As the pressure drops in the tank when you make a draw the pump kicks on and everything starts over again.
To check, take something metal and start rapping at the bottom of the tank and work upwards. You will hear a "clunk" in the bottom half full of water. On the upper half you should hear a "clink" because the upper half should have nothing but air in it. IF the sound doesn't change or changes close to to tank top then the bladder tank must be replaced. Your air setting on the tank should be 2 pounds UNDER the cut in point in the pressure control box. If your pressure control has a 20 PSI cut in and 40 PSI cut out the tank pressure should read 18 PSI. This should be done with the pump off and no pressure in the system. Hope this helps and thank you for rating my reply. Tom