Good day, this calibration test is a real torture test for any printer when it comes to no room for error., this print tests the retraction, overhang and layer bonding all in one; looks can be deceiving especially with such a simple design. Their is only 1mm layer at the bottom and it is part of a hollow cone inside of a hollow circle fused with a hollow cylinder. the bottom layer is hollow and must remain that way.after filling the top hole with water. Take a look at GOOD DAY.txt for more info and make sure to scale it as you may need it.
100-300 micron (.25 - .4 mm nozzle recommended)
100% rectilinear (a must)
Take a look for GOOD DAY.txt for more info on how to print. My personal experience with filament has lead me to believe filament properties may have something to do with layer bonding issues and simple things such as a small draft of air or a speck of dust may also affect the final print. The intention with this calibration test was to figure out why many rolls of filament were being discarded while trying to print watertight designs, the answer was not a a simple word or number and proved that even the slightest of error in any area made this task impossible. The design as is will most likely succeed without error but that is no fun, PLEASE take a look at GOOD DAY.txt for more info (I can't stress this part enough!). Good day and Good luck.
p.s. It is absolutely possible to print large water tight prints with zero leaks.