Gather your supplies. Wash your hands with soap and water for at least 20 seconds. Once the NG tube is in place, attach a syringe to the other end of the tube by twisting it closed. Slightly pull up on the plunger until there is a small amount of fluid in the syringe. Remove the tube from the tip of the syringe. Squeeze the fluid from the syringe onto a pH test strip. Match the color of the strip to the corresponding pH level on the chart. The tube is correctly placed if the pH is five or less. Attach another syringe without a plunger to the NG tube and twist it closed. Pour your child's specified amount of formula into the syringe, wait for it to fully drain through the tube into their stomach. Pour a small amount of water into the syringe, let that fully drain through the tube into their stomach as well. Remove the syringe from the tube by twisting to release it. Place the cap back on the end of the tube. Wash your hands with soap and water for at least 20 seconds.