Here is my modification to the bottle caps @karenwslp made. After several leaks, and a need to just pull the tubing free during reservoir cleaning, I came up with an improvement to the bottle caps. Oh and these caps are from Poland Spring sports watter bottles. Just in case you can’t read the steps:
Step1) remove the blue cap.
Step2) Remove the plastic “Y” piece.
Step3) Insert 1/4 inch coupler onto top part of cap (hexagon shape in cap)
Step4) Insert size “00″ flat washer inside cap. *note use pliers to push it in
*use a little bit of aquarium silicone on the coupler before inserting it into the bottle cap to add extra sealant!