I was afraid of the tendency of vinyl to bend over time, like gas tank straws that make it empty on 1.4 tank… Then I found this copper tube, ahh, fire….
I did the solder. Should not be as much vibration as an electrical thing since it is atop a plastic jug of water to dampen it.

Had to get fitting really hot, then just dripped it in.

The copper I had laying around, so will need to straighten it and cut it to fit later.
I figure the copper will never wander around in the tank.
Homedrpot or Lowes is so woefully understocked on fittings, so I only had option of a straight fitting, not an elbow. The ACE around here has everything known to man, but too far a drive…