Well, I went and picked up the new grow bed with the drilled hole for the siphon.. I was really impressed with the amount of plastic containers available :)
I measured the depth of the grow bed, and decided I don't want anything more than 10cm of water in it. So I cut the siphon tube for 10cm
I also cut stripes for water to come in the siphon bell..I might make them larger to allow water to drain faster, I still need to experiment with that.
Note that water will stop at the highest stripe, and I wanted at least an inch of water in the grow bed. I thought it will keep the system rich with bacteria, in case the water pump failed.
The lower part of the bell siphon is just pipes shaped to help direct the drained water, where I wanted it to go. The setup is in the living room and I didn't want water splashing everywhere :)
That's the setup for now.. The water is circulating properly, but the pump speed is almost the same as the drain speed, which means, the grow bed can never be empty. This is not good, as too much water can drown the plants. I need to tune the filling to happen in around 20 minutes and the drain in something around 5 minutes.
Once I get that done, I'll fill the grow bed with hydroton, which are little clay pebbles the size of marbles. Get the plants and the goldfish
If you have any questions, feel free to leave a comment