This is another aquaponics setup, using the Swivel Valve (Loop Siphon) this is a setup where you need to use many smaller growth bed with a pump and a valve. The idea is to save cost.
Above diagram show the setup, growth bed must be on same level, interconnecting pipe the 50mm bottom of growth bed is subject to your layout.
Above diagram show level of water the siphon action will start, to adjust this level, swivel the siphon to new position.
Siphon stop as soon as the water level reach bottom of growth bed once air is being suck in. The pump cannot be to powerful, because in this kind of setup water inflow must not be more then the siphon can handle.
The reducer (50 ~ 25 mm) at the siphon is to ensure system siphon with smaller pump, and create a positive siphon with a bigger pump, due to it venturi effect. The length of the final 25 mm pipe, I use about 6 inches and drilled holes around it, the length to create enough suction and the holes to cutoff the water better.
This valve is still under evaluation, some final tweaking may be required.