Copied from another thread because I’m describing my system here;
I run an RDWC system. Think of an Undercurrent, only the recirculating pump is in the control bucket (‘epicenter’) and it feeds a manifold that delivers water directly to an elbow fitting in the lid of each tubsite. That water drop is the waterfall.
Water then runs via gravity back to the control bucket through lines near the bottom of each tubsite. The control bucket also has the coil for chilling the water.
I did it this way after noticing that in a standard Undercurrent system, the best oxygenated bucket was the only one they didn’t want you putting plants in!
Having a waterfall in the lid means that there is more churning and movement in the bucket for the roots. It automatically oxygenates. It breaks surface tension, preventing any surface scum from forming. The splash wets the bucket so the plant gets watered no matter what the water level is, making water level much less of a factor.
My chiller has been down for a month and my plants are healthy. Apparently this approach even eliminates the need for chilled water, which to me is an amazing benefit!