I was having a hard time finding what i needed local. I am using a 5 gallon paint bucket picked up from lowes with a lid. I am using Distilled water for cooling the K40 laser cutter and I didnt like the idea of just having the tubing pass through 2 holes in a bucket lid. Drilled 2 holes for the barbs to slide through with a fastened nut on the under side of the lid. For leak proofing the lid I would mayble ad a dab of silicone our use a rubber seal between the nut and the lid.
These buckets have a little flex in the lid which I actually perfer as if the tubing gets moved some there is some flex in both the tubing side and the bucket side so I dont have to worry as much about the pla getting broke by accedintal tension on the plastic.
Disclaimer: I do not know how well this design will work long term. Use at your own risk and with caution. For me so far this has worked with my initial testing but I plan to replace with an injection molded part thats desinged for this for the long term. We are dealing with high voltage and water so yeah be careful.
For the barb fitting I printed standing up with the thread side up Used supports for touching the build plate only printed at 0.2 resolution with 45% infill 3 walls
For printing the nut I increased the size of the part to 102% Uniform scaling. At 0.1 resolution 45% infill and it fit perfect. Depending on your printer settings you may need to adjust differently. The heavy infill may not be needed but I wanted to make sure the part wouldn't leak but that will also depend on how dialed in your print walls are. If i was going to try to use this for long term application I would maybe epoxy coat or something similar to make sure I got a good seal and added strength.