However, it has a shortcoming. When the fluoride filters are installed to the base of the top receptacle, they go so deep into the bottom receptacle that the water will only fill up a few inches of the bottom receptacle.
Child's mother suggested a solution. If the top receptacle could be lifted higher, it would allow more water to collect in the bottom receptacle.
While at Home Depot on a different errand, I noticed a duct that seemed like it would perfectly fit the bill.
|Master Flow 8 inch Starting Collar Take Off - Snap Together|
|Worm gear clamp. Two 4" diameter = one 8" diameter|
A quick call to Child confirmed that the diameters were the same, so I bought it, along with two four-inch-diameter worm gear clamps that I could attach together to make one eight-inch-diameter worm gear clamp. It worked great.