A gastrointestinal balloon system includes a gastrointestinal balloon and a check valve located within the gastrointestinal balloon. The check valve is configured to allow fluid flow into and out of the gastrointestinal balloon. The check valve includes a string coupled to the check valve, the string having a loop on a proximal end and a catheter having a lumen. The lumen is configured to receive a grasping tool. The grasping tool extends out a distal end of the catheter for grabbing the loop to align the catheter with the check valve. Also, a check valve, two-wat valve, and method of using the same in a gastrointestinal balloon.