We bought a timer. Yes, we could have used Arduino boards to run our system for less money, this percentage timer cost us $200.
but since this system will be used to visually demonstrate aquaponics how it works, we wanted to put a mechanism in with big knobs and numbers that non-technical visitors would be able to understand.
This Percentage Timer shown below is what we are using. The dial on the left can set the cycle to any time period between 30 seconds to 24 hours.
The dial on the right turns on the pump for the percentage of the time period chosen with left dial.
W select the time period to 1 hour, with the pump running 5% of the time,which is 3 minutes, the time it takes to fill the beds until the siphons start.
We installed a very high-flow Pondmaster 12 1200 gallon (4550 liter )per hour pump to fill all five beds quickly.
Next we had to figure out how to deliver water simultaneously to all 5 horizontal korrel beds.
My Idea #1 was to use a manifold used for irrigation systems. It did NOT send the equal amount of water at the exact same time to each bed, so I came up with Idea #2.
Shown below is Design Idea #2 :I made a manifold of PVC pipes to fill the beds.
Since the pipes were different lengths, water still did not arrive at the beds at the same time.
Then my husband designed #3, shown below, inspired by an exhaust manifold for a car engine.
We named it the 'Pentapus' ( 5-legged octopus )
The five 'legs' are flexible clear plastic hoses of the same length. It's fun to watch the water and bubbles flowing through them.
This Pentapus gets water delivered to all 5 beds at exactly the same rate and time.
But the siphon timing was still different between the beds...
Looking closely, we could see that the original siphon pipes were made of different thicknesses of PVC!
Also the man who built the system the first time... had cut them to slightly different lengths… no wonder they would not synchronize!
Apparently the original builder of the system also had a problem with siphon timing, which he tried to solve by drilling holes at the base of some of the pipes.
We filled all the holes he drilled with hot glue...and replaced the pipes with other of the same length and wall thickness.
We put in an additional set of positioning screws farther up on the siphon pipe ( I forgot to photograph the second set ) so the parts of the autosiphon would be unable to wiggle and change the siphon flow.
And we hot glued the media blockers to the blue plastic barrels to keep the korrels from getting under them.
I made very attractive screened covers for each media blocker, ( I forgot to take a photo of them )
so korrels couldn't fall in from the top of the beds, either.
The siphons are super reliable now.
Next we did timing tests.
The orange plastic barrels full of rocks are filling up space instead of korrels, as we test the system. we ran the system a lot of times and made adjustments to the siphons until they all reliably would start within 30 seconds of each other.
With the barrels of rocks in place, we didn't have to worry about korrels getting everywhere as we worked on the system.
I left the system to run every half hour for several days, the siphons still were synchronized.
Then we filled the beds with korrels.
Below are our synchronized drains pouring into the fish tank.
Rebuilding this system was so much more work than I originally expected!