To begin with I made five holes in the bottom of the cup. Somewhat small as I do not want the filter medium to go thru.
Step 1: Begin, make the holes
Next, I added the medium, activated charcoal for the final (bottom) layer and washed sand for the upper layer. The sand is mostly to trap material like leaves etc … before the water continues to the activated charcoal.
I used a smaller cup for the sand and a larger cup for the charcoal, so they nest together. After the water drips from the sand, it runs into the charcoal and finally into the final receiving vessel. I’ve used a coffee filter here, but also I’ve done this without the paper coffee filter.
the bubble top came from a whipped cream coffee drink and a 2 liter soda bottle screws into this nicely, creating a reservoir for the dirty water going in .
The water then goes into the cup with the sand, then drips into the charcoal, then drips into your final clean reservoir.