Thanks for all the good tips everyone. This is my first experience using Slime tubes and didn't realize that it was important to position the valve at the 6 o'clock position when filling. Meanwhile, i discovered inside the box the tubes came in the special instructions for installing Slime tubes. The outside of the carton had instruction for standard tubes which mislead me to think there was no difference in using Slime tubes.

Thought I share the instruction sheet I found in the carton. It has a lot of good information oh how Slime tubes work. If you can't read the text in the image, click it and use the magnify tool to enlarge. Thanks again!