Gardening can be an incredibly satisfying hobby, as can be keeping fish as pets. For @CO and me, combining these two hobbies is where it's at! Not only do aquaponics systems offer you the chance to grow food for your family, but they also maintain a healthy ecosystem for your fish, so there's next to no worrying about the quality of your fish's water.
We got into aquaponics a few years ago and have slowly learned and improved our systems over time. We now have 3 separate systems in our house. One that's a bit utilitarian, and two that are (if we do say so ourselves) rather beautiful.
This week, we upgraded the grow bed in our largest system. With this one, we started out experimenting with a gravity fed system, where the water was pumped up to the high side of a gutter and flowed out of the low side. This provided a steady stream of nutrients to the plants, but it was undersized for our 150 gallon tank and didn't clean the water as well as we wanted.
So we went back to our proven bell siphon design. It allows the grow bed to fill with water and then trigger a siphon that quickly empties it. This ebb and flow, or tidal, method of growing is great for plants as it delivers nutrients to all of the root surfaces when the bed floods, and then oxygenates the roots when the siphon kicks in.
We've included links to our video below as well as some useful links to learn more about siphons and aquaponics.
We used xDesign to design our own version of a bell siphon inspired by the Bigelow Brook Farm design. I'm really proud of the unique geometry on the end of the snorkel, and the fact that the whole part can be 3D Printed (upside-down) without any supports. I took extra care to model everything in such a way as to always have self supporting geometry. That way there's no post-print cleanup, and more importantly, the water and air flows are completely unobstructed.
We designed an upgraded grow bed in SOLIDWORKS and build it out of plywood and poplar. We added a rubberized tape to the under side of the bed to keep the water that the fish might splash-up from damaging the wood, and inserted a pond liner in the bed to make it truly waterproof.
Check out the full video to see how everything came together:
Feel free to download this zip file that contains native xDesign and SOLIDWORKS models, as well as STEP and STL files of the design.
Useful links to learn about siphons:
Bell Siphon Principles: http://www.affnanaquaponics.com/2010/02/affnans-valve-detailed-explanations-of_9459.html
Better Bell Siphon: https://youtu.be/4hHRe3KJfoY
How does a siphon work? Ask This Old House: https://youtu.be/LmsIYwf8QqQ