Hey fellow Clowders...
While we are on the subject of tanks I wanted to share this:
I was thinking about the fact that I have heard you should fill your carto before inserting it into your tank.
Of course, I had to be different...

so,

I thought about the silicone pin that comes in the bottom of some of my cartos, the loose one that is separate from the condom and resembles a tack.
I put my carto through the tank bottom-cap that was already in my tank, leaving the tank top-cap off.
I put the tack-like silicone pin into the top of the center-straw of my carto, dripped e-liquid in to fill it up, and finished filling my tank.
I put the tank top-cap over the carto, pulled the pin out by gently lifting it out with a paper-clip, inserted my drip-tip and was ready to vape.
This works well for me, better than trying to fill my tank carto up outside of the tank, with the bottom punched-hole in the carto-casing.
No wasted e-liquid and no mess from the e-liquid coming out of the bottom punched-hole of the carto-casing because it went into my tank and not into the center-straw and everywhere else.