Pay attention to print setup (see the screenshot), as the mesh is created by slicer and not modeled in CAD.
NB: There is a tiny nub modeled in drinkwellplatinum_ezbox_up.3mf – make sure the nub is on the up side. You might need to turn that part over in slicer.
Please use food-contact certified filament. I'm using Fillamentum CPE HG100 Natural (clear), but there are many alternatives.
The charcoal should be around mesh size 8x4 (2.4 - 4.5 mm). You can adjust the mesh size of the printed container a bit but if you go too fine, the pump will not be able to overcome the backpressure induced by the mesh. Experiment if you want :)
The author remixed this model.
Radically simplified(only two printable parts), doesn't need rubber band, mesh is also printable