Backyard Aquaponics
A place to discuss aquaponics

We are at the stage to build our first aquaponics system. We will be living in the bush (St Andrews, NE of Melbourne) and will be living a self-sufficient and off-the-grid lifestyle.
Before we commit to such an investment we want to ask the experienced people on this forum to take a look at our design. We would like to receive some honest feedback, be it negative or positive.
The shed is a Ranbuild shed 12000 long, 5000 wide and with an eaves height of 3000. The shed will be cladded with Colorbond panels on one side and clear polycarbonate panels on the other side. The clear panels will convert that part of the shed in a greenhouse. We've discussed this design with Ranbuild and they stated they can commit to this project but we need to put in cross braces in every bay. We are still working on the ventilation system for the shed but we were thinking of installing a ridge vent system made by Apex and some louvres who will be operated by linear actuators.
We will have 3 IBC's in series for our fish We want to have the opportunity to raise different types of fish and of different sizes. Say, one tank will be silver perch, one tank will be golden perch and the other tank would be bass or trout. In the same area we will be breeding our rabbits as well (But that's a different story).
Underground we will have a 2500 liter rainwater tank which acts as a sump tank and where we will have our pump installed: An Aquamaster MKII 4900 (3500 liter per hour at a head height of 2.5 meter).
The pump will flow into fish tank 1, which will overflow in fish tank 2 and the latter overflows in fish tank 3. From there on we will go through a swirl filter and then to the growing beds. The system will be a CLFT/PIST.
We haven't worked out the plumbing yet to the different growbeds but are working on it.
The growbeds will be made out of Aquaplate Colorbond metal and will have following dimensions:
1x 2700x850x320 (667 liters)
2x 1800x850x320 (419 liters)
4x 2400x850x320 (585 liters)
1x 3000x1000x320 (866 liters)
In total we will have 4711 liters capacity in the growbeds.
One of the growbeds will be used as a DW Raft in which we would like to put yabbies. We could also put yabbies in the sump tank.
We would also like to grow duckweed but are not sure yet how to incorporate this.
Anyway, we hope this will give you an idea.
The whole setup will be automated by using an Arduino based control system with 41 inputs (Of which will be 12 temperature sensors daisy chained by I2C) and 11 outputs. We will be continuously monitoring pH, temperature, pump flow, DO, high and low levels in tanks, turbidity, aeration, etc. The outputs are for ventilation systems, back-up pump and main pump, heater element (When required), etc.
We would like to receive some suggestions about what sort of ventilation system to use. Remember we are off-the-grid and want to utilize as many passive systems possible.
We've spent about five months on designing this system but we never had an aquaponics system before. So, that's why we publish this design first to receive some input or opinions.
Once we start building it we will publish the whole process step-by-step.
Many thanks in advance for your feedback.

Hello mate, looks like a great shed. I've had a skim thru your idea and the ft's flowing into each other wouldn't be in my line of thoughts with solids transferring and the tanks acting like settling tanks. Having a slo and pump feed to each tank would be better (IMO), even using an aquaponics indexing valve. I'm also partial to circular ft's due to the ease of creating a current helpful with solids removal. (Less maintenance)
Of course using a slo means the ft water surface level needs to be higher than the gb surface height.
Anyway, good luck and look forward to following your build.
Not quite sure why you want to balance your shed on a cylinder either.......

Luc, looks like an ambitious and expensive system. I'm surely not the most experienced guy to offer suggestions. Started last July, but a few suggestions:
1. I would start smaller and "get your feet wet", before investing in that large of system. Small system equate to small losses, even with big mistakes, where as even small mistakes in your large system, could prove costly.
2. There are some very good threads on here for off grid systems and back-ups. Not sure anyone has as large a system as you completely off grid. How are you supplying power? Solar? Will need a large battery bank for back up.
3. You'll certainly need some large exhaust fans for the GH. proving a major problem in my GH...not enough ventilation means lots of disease issues.
4. Maybe better to be on grid, with off grid backup??

Good luck man. it looks like an awesome setup once it's complete!

Skeggley,

Thank you very much for your feedback. Your advice to feed the tanks as a parallel system instead of a system in series makes sense. I had been thinking like that along the line but thought that water from one tank could flow into other tanks if the piping wasn't completely level. I could always lower the exit pipe by a couple of centimeters to prevent this. I'd forgotten to mention that I would definitely use SLO in every tank.
Circular tanks would be great, however, they come at a price. IBC's are much cheaper.
The fish tanks will be elevated from the floor by an extra 30cm or so to create more height difference between FT and GB.
I had a giggle following reading your remark about the balancing act.
Many thanks for your reaction! Very constructive.
Luc

Coachchris,

The shed will be built in a couple of months time. I will need to put the sump tank underground before I start building. The shed will cost us roughly $21,000 and the ST will be roughly $2,500. So, by then the majority of the investment will already have been made. Over the last year I have been reading lots about AP and also about the varying successes from different AP-owners. The majority seems to be very successful. We know we take a risk by starting "big" but at least we've done our research. Starting small would mean investing in parts which will become obsolete later on and a small system would not really behave the same as a bigger system. We understand and appreciate your point.
2. We have a 20 acre property in the bush and will have a 5.5 kWh off-the-grid PV system with battery storage. The system will supply 15 kWh a day for 3 days at no sun. We got a back-up generator as well.
The only power the AP will consume is 81 Watts for the pump (2 kWh per day), 30 Watts for aeration and about 10W for various electronic control systems. So, we've got this one covered.
3. Yes the ventilation is my biggest concern at this stage. We want to install a ridge vent over the whole length of the shed. Also louvres could be installed on both sides of the greenhouse and maybe an electric fan in case it's becoming extremely hot. We could afford the extra load as most of the time when it's really hot there is plenty of sunshine as well and our PV-system will be able to generate 30 kWh+ per day under full sun.
Our major concern is that the water would become too warm when it goes through the greenhouse grow beds. At least teh ST is underground and will hopefully moderate the water temperature before it goes back into the FT. This is our biggest unknown factor.
4. We have access to the last power pole on the grid but we refuse to hook up. Using the power companies is like dealing with the mafia. Currently we are paying about 32 cents per kWh to the power companie. Our PV-system will provide electricity at 38 cents/kWh. With pending rises in electricity prices we will be breakeven pretty soon and than we will be laughing. Our PV-system is a proven concept. My neighbor has got one as well and I've been following it over the last two years. There hasn't been one single blackout yet. (Touch wood).
Thanks for your feedback!
Luc

Not necessarily. Instead of the SLO's feeding the growbeds, they could drain into the swirl filter, then clean water back into the sump, and the pump in the sump could pump to the fish tanks and growbeds.

ie: sump > fish tank > swirl filter > sump
and:
sump > GB > sump


The growbeds in this case could be the highest part in the system.

Another advantage of this method is it's easier and cheaper expanding and adding on growbeds etc as you would run the inlet plumbing to the GB's under pressure in 19mm-25mm PVC or LDPE, instead of 50mm PVC which is commonly used with the SLO > GB configuration

Nate explains it well in this video:

http://www.youtube.com/watch?v=p9nP9O26mBg

A disadvantage of the above method is of course less solids would be put through the GB's.

EDIT: LRAT any reason you are opting for a swirl filter instead of a radial flow filter? The common consensus out there thesedays is that RFF's are more effective at removing solids.

LRAT, I'm also a bit concerned about lack of ventilation in this design. Doesn't seem to be enough cross flow.

In addition to the opening roof vents, could you look at cutting some ventilation panels on the sides of the shed close to the floor? eg I'm imagining some flyscreened openings with covers over them which could be opened and closed depending on your temp and humidity requirements. This would help with cross flow, sucking in fresh air down low and expelling the hot air out through the roof. I'm not sure if the shed manufacturers would approve of this though as it would change the weight bearing specs of the shed walls etc?

I'm a big fan of the whirly gigs/twisters on the roof for passive ventilation. I installed 2 on our house roof this summer (approx 100m squared roof area) and it has made a huge difference in temperature. They range in price from around $100 - $200 each, but after the initial cost they provide free, passive ventialtion for 20+ years. When its really hot, they spin fast, when cold, they dont spin much at all, so in a sense they are self regulating and passive in the true sense of the word - no arduino or electricity needed to operate them

Jono81,
Thank you very much for your opinion! You gave me some really good food for thoughts. I had never considered of filtering the water from the FT's through a radial flow filter and than back to the ST. Yes, that would get rid of nearly all the solids suspended in the water. I've been watching most of Nate's video but didn't see that one.
I have to admit that I used the wrong terminology when I was talking about the filter; yes, I intended to state radial flow filter (Sorry, English is my second language).
We've got two whirly birds on our other shed and they do a great job as you described. However, I am looking for something that can be closed during cold spells to preserve some heat inside the greenhouse. The ventilation slots on the side near the ground is something we could incorporate in the design; we are just looking for some existing ventilation systems which could be bought of the shelf.
The ventridge we had in mind looks something like on the picture as below.

http://www.apexsteel.com.au/sheetmetal/ventridge.htm

Thanks for the ideas.
Luc