Thanks for the link, read it, plus your comments, now makes sense. The water drips in the top/netcup, and drains out the bucket-bottom to reservoir. Still don't see what makes the water back up until it reaches the netpot/overflow at top of bucket, seems like it would just drain back to res.
Doesn't matter........ Now if we replace that DWC bucket filled with liquid with the same bucket filled with grow rocks, and put a second bucket beneath the first one [like KFB] so you can remove the top bucket to clear the drain, it would be the system I'm envisioning. A waterfarm! [well a Waterfarm without the noisy air pumps].
The only question then is whether to let the bottom bucket passively drain back to res or have a second pump flowing water into/out of it, then through all the other bucket's bottoms, from one to the next, in a line. And back to res.
Would there be any advantage in that last step?