The water enter via the green garden hose almost at the bottom, sets up a whirl pool, and exits via four points
The first exit is a small hole in the standpipe (not shown in the video) The second is the black plastic leaf skimmer that we see taking out some floating duckweed, the third is the bell siphon (big white thing in the centre). All those three water exits go back to the grow beds and take solids with them.
The other exit is to the NFT tubes and is the clear plastic tube that we see first up. A few things look like they nearly get sucked ito it, but it actually does a pretty good job of only taking clear water. This tube is set just below the low tide that the siphon creates.
As far as I know this is an original idea, but I've been wrong before. Rather than my usual disclaimer, this time I offer nothing but this.