There is a constant 1/4" of water in the bin for K-8 veg bin that is completely changed out 4x/day because of the volume that enters from the top from the 6 drip emitters in the Maternity Ward for 15 minutes. Hehe, even the slight "waterfall" sound is a welcome unintended effect from filling from above. Kinda sounds like a tabletop water fountain.
I imagine it's very soothing and Zen like.