Here's an easy aquaponics growbox design that's been filtering a tank and grown food/other plants for me.
It's been working for two years with this simple ebb&flow pipe without missing a beat. Which is far better than I can say about any bell siphon I ever tried to come up with…
Filter cloth to the ends of the drainage tube:
Safety overflow (in case the other gets jammed) and an inlet for the ebb&flow pipe:
Sliding the drainage tube on the inlet:
Pre-glued pipe, gaskets, vaseline:
Pipe installed into the inlet:
Basic level of the water at the start of the siphon:
…can be adjusted up (longer cycle)
…or down (faster cycle)
…or stopped altogether (in case you need to keep the water high and let the overflow take care of the flow)
There. Easy and cheap.
Now just fill the box with the growbed material of your choice and install a pump to get some water flowing.
Thanks of looking.