Grow Beds, Gravel and Siphons

It's been a while since I've updated this.  I've been too busy attending weddings, teaching Brazilian Jiu Jitsu and getting ready for another trip to Brazil.  While the bloging has been slack, I have managed to make time however for some meaningful progress on the system itself.

One of the trickiest parts of this operation so far has been the construction of the grow beds.  After much research I ended up making them out of plywood and lining them with Fireston Pond Gard EPDM rubber.

Frame made of plywood

Lined with EPDM rubber 

Very happy with how it all fits together

The next part was to build the siphons that will take the water from the grow beds back to the fish tank.  This involved various prototypes and failures before I got them working correctly.

It took several attempts to get the bulkhead to seal

Media screen to keep the gravel out

Bell siphon

Complete with gravel.  Second pipe is to gauge the water level.

I ordered a 12v pump and converted an old ATX computer power supply that I had around the house to power it and the other electronics.  To keep this all out of harms way I built a little shelf under one of the beds.  Soon I will tidy up this mess of wires and put the micro-controller in there as well to run everything.

System complete and cycling

Now that the system is complete I have left the pump to cycle water from the fish tank (no fish yet) up to the grow beds and the back to the fish tank via the siphons.  This will further rinse the gravel and give me a chance test the reliability of the setup.  The next step will be to build a swirl filter to remove any uneaten fish food and other waste on it's way from the tank to the grow beds.