Building The Aquaponic System - Part 1 of 3

Here is the first of three videos on how the aquaponic system is assembled in the geodesic dome.  This first video recaps some of the installation that was done during the dome construction and shows a general overview of how the entire system operates.



Hi, I’m Rob Torcellini

This video series will show you the various details about how I set up the aquaponic system in the geodesic dome greenhouse.

This first video, I’ll explain how some of the components were installed during the dome construction.  I grouped the video sequences by the component, not in the chronological order of when they were installed.

First is the central sump tank.  This tank is used to catch all the water that is draining from the grow beds and a pump returns the water to the main fish tank.

While the foundation hole was empty, I built a brick wall around the tank.  The wall leaves a gap around the tank so that it can expand and contract when the temperature changes. If this wasn’t installed, eventually backfilled dirt would crush the plastic tank.  The end of each pipe draining into the sump has an elbow to help swirl the water inside the tank, which will help to reduce sediment buildup.

Also while the foundation hole was empty, I installed a large sump tank which is used as a buffer to compensate the changing water levels in the grow beds.  The water from the fish tank drains into this tank and then pumps the water into the grow beds.  This tank holds about 500 gallons of water and has a cone bottom, allowing sediment to work its way down and sucked out by the pump.

This tank also has a block well-housing built around it to protect it from getting crushed.  This is a view of the central sump and buffer sump wells while they were being backfilled.

There is a network of drain pipes that are buried under the floor.  These are used to collect the water from the assortment of grow beds that are throughout the dome.

The drains are 2” lines and are set at a slope to drain the water into the central sump.  There are extra drain inlets that come up to the floor which will not be used, but at the time I installed this, I had not decided on the final layout of the grow beds.

All the pipes are backfilled with sand to protect them from damage. This allows me to easily dig them up if any maintenance needs to be performed.  After I lay down the final floor, the drain pipes are cut flush with the floor.  If any dirt or insects fall into the pipes, they will just get flushed into the sump tank.  Here is the final view of the drain pipes with the central sump tank.

The last component is the main stock tank.  This is placed in the northern section of the dome to help minimize light and algae growth.  The tank is a scrap tank that I salvaged and it had a bunch of fittings that needed to be capped.  After leveling out the area with a sand base, the tank slid right into position.  While I was installing the drainage pipe, I buried a scrap section of 4” pipe between the sump and fish tanks.  This allowed me to run the pump and electrical lines between the two tanks under the floor. Since the tank was so tall, I wanted people to be able to easily see the fish so I installed 2 windows.

This is a functional overview of the entire system.  Water from the fish tank overflows into the buffer sump tank.  It is constantly pumped, along with any solids under the floor and into the grow beds.  The line to each grow bed has a valve to help regulate the flow.  There is also a line that feeds back and shoots water back into the fish tank to help aerate the water.

Using bell siphons, the grow beds continuously flood and drain.  The inner beds drain directly into the sump tank, while the outer beds drain into a raft system (not shown), which then drain into the sump.

There is a float switch in the sump tank that pumps the water out of the sump and back into the main fish tank.

The large sump tank is use to maintain a consistent water level in the fish tank.  Since the levels in the grow beds and central sump tank are constantly changing, that difference in volume has to be offset elsewhere.  Not only does this help with the water levels, it adds additional thermal mass to help keep the water temperature from fluctuating each day.

In the next video I’ll detail the plumbing installation.  Thanks for watching!

Butterfly

While I was filming my latest video, this butterfly landed on my hand.  In the past, I’ve received several questions about why I don’t put screens on the greenhouse vents…this is why!

(Sorry it’s blurry, this is a screen grab from the video and the camera wasn’t focused for the close up shot!)

Automatic Fish Feeder

Time to add to my laziness and add some more automation.  I no longer have to feed the fish a few times a day...however I still like to just stand there an watch them.  What is it about them that's so mesmerizing???




This is a small automatic feeder that I made which holds about 4 tenths of a liter of fish food and has been running for a few years.  I built this larger one for the new greenhouse which holds 2.8 liters.

The feed is controlled by a regular 3/4 inch wood auger bit which fits nicely into a housing which is a piece of 3/4 inch black pipe.  This is driven by a 12 volt DC gear motor I got from a surplus store.  This is a great motor since it has a slot instead of a drive axle so it’s easy to make the auger bit fit into it.

First I cut down the auger bit to the right length and grind down the shaft so that it fits into the slot of the gear motor.  I then cut out the center of the black pipe.  This is where the feed hopper will connect to the auger housing.  A small piece of flat bar is used as a mounting bracket which will allow it to be mounted to the tank and attach the motor to the shaft.

After carefully setting up the pieces, I tack weld the auger housing to the mounting bracket, then remove the motor and finish welding the pieces together.

The feed hopper is made from an old computer cover.  I made up a cutting template for the various pieces and sprayed adhesive to the cover to hold the templates while cutting.

I built in some tabs to the hopper walls so I could weld the pieces together.  This is the point in time where I which I owned a metal break, but had to improvise with my vice and hammer.  Luckily, the bends were not too complex.

After all the pieces were bent into shape, I ground off the paint so the seams could be welded together.  I also drilled holes through the walls where the tabs would connect.  This is so I could weld a tack through the hole to connect the thin sheets together.  It’s similar to riveting the pieces together.  

When the hopper is welded together, I grind the welding tacks down so they are flush with the sheet metal.  The last bit of welding is to attach the auger assembly to the hopper.

I am fortunate to have access to a nice sand-blasting cabinet.  This quickly and easily removes any loose paint and rust and makes a really clean surface to paint.  After a couple of coats of paint, it looks almost as nice as work done by a pro ….almost.

I made up a level switch that turns on an LED to let me know when the feed is getting low in the hopper.  I took a bamboo skewer and hot-glued it to a micro switch.  The newly extended lever reaches into the hopper and has a float that hangs from it.  When the level goes to low, the float will pull down on the lever and light the LED.  I also added a momentary switch into the box which allows me to turn on the auger in case I feel like giving the fish a bonus snack.

I mounted the level switch box to the hopper and connected the motor wires through the box.  Then the new feeder was bolted to the side of the stock tank.  For now, I connected the feeder to one of our IX-180 index timers.  It is programmed to run the auger bit for 20 seconds, four times per day.  The extra input of the timer is used to monitor the water temperature in the tank.  Eventually, the feeder, vents and other controls will be connected to a master automation system.

Here’s the float that sits on top of the food, when it gets low enough, it just pulls down on the lever and turns on the LED and this is the feeder in operation.     Thanks for watching!  Make sure you subscribe to this channel for more great videos!

Adding Automatic Vent Openers

I finally get to work on some of the more exciting things in the dome.  Automation!!!  I love being lazy!




A few years ago I made up some vent openers which use windshield wiper motors. They work well for the small greenhouse, but the frames have had some structural problems in strong winds.  For the dome greenhouse I’m using linear actuators to operate the vents.  The actuators have a lot more lifting strength and can withstand stronger wind forces.

To attach the actuator to the window frame, I took a piece of angle iron and made a cross brace.  The brace will fit about half-way up the vent.  I cut off a section from each end so that there were tabs that would be used for bolting the brace into the face of the vent frame.  I then welded a couple of tabs into the bracket which provided the connection linkage for the actuator.  After rounding over the edges and cleaning up some of the welds, the bracket was attached to the vent frame.

The rest of the braces are standard steel bar stock that are bent at slight angles.  There are four of them which go from the greenhouse struts to the back side of the actuator.  Because of the odd angles of the dome, a few of braces need to be bent as compound angles.  If this was a traditional vent the angles would have been much simpler bends.

I temporarily bolt the top brackets to the back side of the actuator and mark where the brackets connect into the dome’s strut.  It wasn’t necessary, but I set the actuator to be level when it was closed, simply for aesthetics.  I drilled out the first hole in the dome strut and attached the bracket.  Once the pieces start to hold themselves in place, it’s much easier to mark and attach the remaining brackets.

The bottom brackets are marked and installed the same way.  It’s just a bit more critical to make sure they are placed properly so that the vent is pulled completely closed when the actuator is fully retracted.  Once all four brackets are secured, the pyramid shape from the triangulation creates a sturdy mount for the actuator.

Now that it’s fully assembled, a quick test is in order.  All the pieces are cleaned and painted to give the system a nice new look!  Once the paint is dried, it’s a quick reassembly and then time to it get wired to the controller.

A regular two-conductor wire is used for each actuator and each vent opener has a line that runs back to the controller.  The actuators have built in limit switches which stop the motors automatically.  To open and close the vent, you just have to reverse the polarity of the power in the wire.

The thermostat controller is a prototype six-relay control unit that can be programmed to set each vent to open on independent temperatures.  The unit can be programmed to sample the temperature at predetermined intervals and also delay the change between relays so that all the vent motors aren’t running at the same time.  This keeps the unit from drawing too much power all at once.  Each relay can also be disabled and forced into an open or closed position.  There are more details about the thermostat in the description area of this video.

Thanks for watching.  Don’t forget to “thumbs up” this video if you want to see more like it in the future and feel free to leave comments too.

All The Dome Videos

I put all the dome videos together in this nice index video.  Just click on the one you want to watch!



Also, Here's a play list that you can click on to queue them all in a row: YouTube Playlist

Geodesic Dome Greenhouse - Part 12 - THE END

This is the final video about construction the aquaponic geodesic dome greenhouse. Don't worry, there are still more videos about the aquaponic system and other projects we're working on!



Hi Everyone.  I’m Rob Torcellini from Bigelow Brook Farm.  This is the last video on the series on building the geodesic dome.  I wanted to thank you for watching all of these.  I’ve had a great time of the last year building this.  Learned a lot, made a few mistakes along the way, but overall, it came out pretty good!

I’m planning on do a short series of videos about how I set up the aquaponics system inside the dome.

I also had this camera shoot about 1500 photos of the entire project that will be in a time-lapsed video.

Again, thanks for watching and we’ll see you soon!


It’s starting to get a bit warm in here so it’s time to add some vents.  I started by building frames that would fit loosely inside various areas around the dome.  There will be a total of five vents and each section will be able to swing open and closed.

Next I removed the existing polycarbonate glazing and then attached the new frame to the dome with a couple of standard door hinges.  In order to get the glazing to fit back into its spot properly, I had to cut it down a bit so that it wouldn’t hit against the hinges or the surrounding polycarbonate when the vent was closed.

I simply held the polycarbonate into the new frame and screwed it into place with the washer-backed screws and the vent was done.  The remaining 4 vents installed the same way, but just a bit trickier for 2 of them since they were 15 feet off the ground.

All of the exterior joints needed to be sealed to help prevent the rain from leaking in between each joint.  I used a clear polyurethane tape which is used as a protective tape on the edge of aircraft wings and wind turbines.  If it’s good enough to hold on to a wing at 500 miles per hour in the rain, it just may be good enough on the dome.  It was easy to apply by just removing the backing and pressing it down with a j-roller.  Once it bonds with the polycarbonate, it’s basically impossible to remove.  After covering each joint I drove a washer backed screw through the tape and polycarbonate.

Wherever there is a vent opening, I applied the tape to the polycarbonate and cedar which created a channel for the water to drain from.  I’m not sure how well the tape will bond to the wood…only time will tell.

Applying the tape on the upper areas of the dome proved to be a bit trickier. I found it to be unnerving being up there with the risk of sliding over the side or dropping through a section of polycarbonate.  I’m happy to say there were no trips to the hospital for this project!

I wanted to use some of the logs that I cut down last year from the site in a couple of areas of the dome and for grow beds for the aquaponic system.  My neighbor stopped by with his WoodMeiser saw mill and milled roughly 1500 feet of white pine into 1 inch and half inch thick boards.  It was a great way to save some money instead of buying lumber and we got to use some logs that would have gone to waste.

Inside the dome I covered the walls with some of the half-inch pine boards.  Each piece is roughly fitted, measured for the proper angle, and cut to size.  Sometimes the pieces had to be cut a few times to fit properly.  It was a very tedious process cutting all the angles, but the end result looks great!

In the shed area, I only filled the walls with one inch of foam to save a little money.  The rest of the wall cavities are filled with regular fiberglass insulation.  The boards on these walls installed much quicker since there are long and have square cuts!

The ice and water shield held up well through the winter but it was time to shingle the roof.  A friend of mine volunteered his crew to help out which was much appreciated.  Even for a professional builder, there was a lot of pondering on how to lay the shingles on the dome area.

On the south side of the greenhouse, I leveled and planted timothy grass.  Eventually, this area will used as a small orchard.  A local arborist was more than happy to get rid of their wood chips so I was able to spread this on the remaining areas that didn’t have any top soil.

The shed area and dome knee-wall is sided with cedar shakes.  They require little maintenance and they help to give a contemporary building a little New England feel.  I also added a small awning over the main entrance to make the building less….boring.

That’s about it.  There will still be more videos in the future.  If you have questions or comments, please leave them in the comments section below and I’ll try to address them in future videos.  Thanks for watching!

The Better Bell Siphon

This is an explanation of how a traditional bell siphon operates. It goes into some of the physics of how the auto siphon gets started and stops. One of the biggest problems I've run into is getting them to stop properly on large grow beds. I've solved this problem with one simple little piece! It's so simple, I'm kicking myself for not figuring it out years ago!

This grow bed is using 3/4" pipe for the drain and standpipe with a 2" bell. The fill rate is LESS than 1/2 liter per minute and the siphon still starts with no problem. It's been running for about a week without any problems.