I am having problems sealing the tube that I inserted in my res. I drilled a
1/4" hole using a 1/4" Poly tubing. I tried liquid nails, RTV to no avail. The res is a rubbermaid brand. What do I need to do to successfuly seal this.

I would recommend JB Weld, I do not believe it will cure underwater but it is water proof, and cures hard as a rock, plus it's in a clay form so you can mold it.