Backyard Aquaponics
A place to discuss aquaponics

OK so I thought now would be a good time to put all our info on here so it can be accessed by everyone. Most of the info is documented on the website in the signature below. If you want all the info now check it our - otherwise I'll start pulling all the good bits over here over the next little while.

Their are three of us developing the system Kasia and Lungi (two teenage girls as part of their science schooling) and myself Matthew - we are located in Panajachel, Guatemala. We have named the project Aquapanaponics to incorporate our location. Status of the project is that we are currently about 80-90% through the construction phase.

Firstly some broad specs:

* Ebb and flow system with no sump tank (see video below).
* Fish tank - 700l water tank. Limited options here and this was the most cost effective. The tank is a vertical plastic tank for water that is commonly used on top of houses here. We were after a horizontal tank (1200l) but it was four times as expensive. Interior is white.



* Grow beds - very limited options here. We started of looking for blue barrels but everything here is reused (not discarded like in Aus and the US) so they are quite expensive. So we found some big buckets ~80l each that cost about US45 each. We only have three so far but hope to find another three.



Here is a short animated video that we made when we were designing the system in google sketchup - http://www.vimeo.com/15034765

More to follow...

Very good. Just remember to keep the stocking of it light through cycle up and thereafter only stock with is appropriate for the filtration you have.
Use what ya got, I like it.

Thanks for the comments TCLynx - I think at this stage we plan to stock pretty conservatively - just enough to get some decent plant production and we may ramp stocking rates after the system is up and running well.

Previous post should read US$5 for the buckets not 45...

So how did we (well I) get into aquaponics? Well last year we started a grand bicycle tour starting in Canada and ending, well here in Guatemala (unplanned, Pana is a sticky place). At some stage along the way I read a couple of articles on aquaponics and what with 5 hours of saddle time a day to contemplate the issues of the world there was plenty of time for aquaponics contemplation/day dreaming.

When we decided to stay here for at least a year it was one of the first things I decided to do. It is the first time in about 15 years that I have been gainfully unemployed so it has been the perfect opportunity to take advantage of some free time. Anyway back to the aquaponics system...

Basic Aquaponics Methodology

This is the basic aquaponics methodology we decided to adopt - I think primaryily because it had the fewest number of components. It is a simple flood/drain system with a single fish tank and water pumped up to the grow bed(s) and returned by syphons.



I think we will end up with a slightly lower than 1:1 tank to grow bed volume so with low stocking rates we should have plenty of water in the tank to accommodate the rising/falling level of water as the grow beds a filled and drain.

Grow Bed Media

There is not a lot of aquarium/gardening stores around to buy stuff so for our grow bed media we headed down to the nearby river to collect some samples. The common materials in the river bed are course sand, gravel/rock and volcanic pumice. After initial interest we did some research on pumice and decided for a number of reasons (it floats, can be sharp when broken up and can weather easily) to go with the gravel. One of the big benefits of the pumice over gravel would have been the significantly lower weight. Here is a pic of type of river gravel we ended up with - typical size is 5mm to 20mm, though when processing we tried to stick to the 10-15mm range. Most of the sewage from the villages up in the mountains flows into the river so the gravel has required lots of washing to clean it.



We did some tests to identify a) how much of the container volume would be occupied by water/media and if there was any difference between media in regards to the flow rate of water through each media type. Results from these simple single sample experiments can be found here: https://docs.google.com/Doc?docid=0Ad7W ... l=en&pli=1. Basically the experiments showed little difference between different media in terms of water flow rates and water/media occupation ratio - which was around 50%/50% by volume.

Were you riding 'bents or uprights on your way down there Matt?

We spent a lot of time on the Great Divide Mountain Bike Route in the USA and some off-roading elsewhere. We had regular upright diamond frames with drop bars and 2" tires (panniers strapped to racks). You can find out more about our tour here - http://www.crazyguyonabike.com/doc/NM2009P1

Handy being able to get gravel from a river. And the washing, well everyone should experience gravel washing that that's all good too.

Have you gotten a test kit yet so you can check your source water pH as well as to check if the media has any effect on the pH?

We have a basic (strip test kit) which we haven't used yet and someone is bringing down a liquid test kit for thanks giving. At that stage we were going to test the water (and test out the two kits).

So are you suggesting we should:
a) test water directly from source and record pH; and
b) soak some gravel in the water (for hours/days?) and re-test water to see if pH has changed?

It wouldn't be a bad idea

So we first started the project in April (so you can see how slow we have been moving). The first 2-3 months we focused on researching a lot of background material on how aquaponics works and the different ways that people setup their systems. This was followed by an iterative period of finding out what we had to work with here and designing a system to match. Only in the last 2 months have we started buying some of the local components and putting it all together.

Though even before we formally started the project I had someone in the US bring us down some of the electrical components that either would not be available here or would cost a significantly more here for the same quality.

Water Pump

This is an Eheim 1262 water pump. It can either be used as a submersible or plumbed externally.



*outlet fits threaded 3/4" pipe
*120v, 60hz, 80 watts
*max flow at zero head - 3,400l/h
*max head 3.6m



I have no idea why I choose this pump or what the real pros and cons for it in an aquaponics setting. I've heard that they are good quality but if/when it breaks we will be using a local pump. So far I have tested it with just two of the grow bed buckets filled with gravel and it does the job in around 45sec. So I think it should be reasonably sized for our system

Cycle Timer
We will be using a cycle timer to control the flow of water from the fish tank to flood the grow beds. The water pump will be attached to the timer and a flood/drain cycle (as yet undetermined) will be set up so that:
*when turned on all the grow beds are flooded to the right level (there will be taps on the inlets to each of the grow beds to adjust and balance individual flow); and
*then turn off to allow the beds to drain and wait until it is time for the next flood cycle.



The timer has the following features:
*rated 15amps @ 120v
*on time between 1 sec and 40 min
*off time between 1 min and 8 hrs
*optional different day and night cycles (based on a light sensory)
*can only control one device

I am yet to decide whether this will live in the house or out with the air pump(s) in a sealed container. I have had a play around with it whilst testing out the pump and it definitely works. The only potential issue I have at this stage is as the adjustment is analog not digital - whether it will be fine enough around the 2 or 3 min mark to accurately fill the grow beds. Time will tell.

Repeat cycle timer is a great thing. +1 for getting it. I wouldn't worry about it being fine enough adjustment though. Just design the grow bed drain such that if the pump runs too long, the excess water will just flow down the top of the stand pipes and not over flow the bed. The extra flow going down the stand pipes for a few minutes after the beds are flooded is actually a good thing that adds extra aeration into the water going back to the fish tank. It is also filtered water so that is good too. So even if it only takes two minutes to flood the beds but the pump stays on for 5 that is just fine, even desirable.

Remember, you want to move at least the volume of your fish tank each hour. You will probably have the choice of running the pump long enough to move that amount of water at one time or you could just run the pump more often to get the circulation needed.

Also, I recommend making the stand pipes such that you can pop them out and adjust the holes if the beds are not draining fast enough or something. If you make the beds drain faster, it will take longer for the pump to fill them.

I would go ahead and test your source water (make sure to bubble it a bit after drawing it from the pipe so you are not getting a false low pH reading) Just to know what levels you are starting with and then see if your media has any effect on your pH. I know of many people who have struggled because their media contained too much limestone. Anyway, I don't think the cinder should be a problem and river pebbles usually are not either. But it would be interesting to know what the test strip kit says and I'm glad you are getting the liquid test kit too since they are usually more reliable.

Leaping backwards a bit to your choice of media, you could always have a layer of pumice on the bottom and an layer of gravel on top. This would stop you pumice floating (and it would eventually fill with water) and give you a lower overall weight.

@TCLynx - we have already gone down the path of installing loop syphons and overflow pipes. I hope we should be OK with some playing around with the timer. The overflow pipes have been placed so that they are at the same level as the top of the gravel. Based on your comments it may have been wiser to put them slightly lower. If necessary we can fill the beds with some more gravel to raise the height (we currently have about 2" space from top of gravel to top of grow bed bucket).

@chillidud - I like your idea. We will almost definitely require more gravel so this could save us some hard work. We have three grow beds full of gravel presently though we are aiming for six and I saw a likely suspect for a new bed in town today.

OK some more info on electrical components...

Aeration System

Below is a picture of some of the key components for the aeration system. The pumps and tubing weren't my first choice but beggars can't be choosers and this is what we have at present.



So the key components are the two JW Pet Fusion Model 500 Air pumps. Each pump has two outlets and can operate "up to 7 ... ornaments, filters and airstones". I did some web searching for information on the air flow and operating depth of these pumps and came back with nothing. An email request sent to JW Pet was more successful and they indicated the following:
-Maximum flow: 200 litres/hr at zero back pressure; and
-Maximum pressure: 3 psi (about 6ft. of water) at no flow

Each pump is rated at a max of 3.5W.

The height of the water in our fish tank should be no more than 1m (~3ft); so assuming a linear relationship we may get 100l/hr of air from each pump though it is likely to be less once air lines and airstones have been added. Each pump has a dial to adjust air flow and the instructions indicate that the pump should be kept dry.

Our intention is to connect both outlets of both pumps via airlines to two 1.5" airstones - so this will give us 8 airstones providing air in the tank. One (or possible both) of these pumps will be hooked up to an UPS (uninterrupted power supply) so that if the power goes off. Here is a schematic:



I also did some digging through Back Yard Aquaponics Members System pages to see if there was any conclusive relationships between volume of water and flow of air required for aeration. As you probably can guess my research was inconclusive (most likely in part due to excluded variables such as tank depth, temperature, altitude, alternative aeration from flow of water etc for each system) but the following information was gathered:

*average flow rate of air (litres/hr), of air pump, to tank volume (litres) is 1.19 (1.19x as much air as tank volume) {13 data points}
*average flow rate of air (litres/hr) to tank volume (litres) for systems smaller than 2,500 litres is 1.54 (1.54x as much air as tank volume) {5 data points}
*average flow rate of air (litres/hr) to tank volume (litres) for systems greater than 2,500 litres is 0.97 (0.97x as much air as tank volume) {8 data points}
*min. ratio of 0.53 and max. ratio of 3 {13 data points}

Our system will have air pumps totaling 400 litres/hr and a tank volume of approx 600 litres - giving a ratio of 0.67, which is at the bottom end of the range. DO levels will be monitored carefully once the system is operating to see if additional aeration is required.

For more info on above research see posting here - https://sites.google.com/site/aquapanaponics/4-project-updates/componentsaerationsystem

Uninterrupted Power Supply (UPS)
Perhaps not surprisingly we have quite a few power failures here in Guatemala, probably one every two weeks, though most last for less then a minute. In our nine months here we have only one pover failure greater then a couple of hours. I put this down to the privatization of the electrical companies here - while the price of electricity here is very unpopular (I think it is aroundUS$0.25/KWh) at least there is a very good economic reason to keep the electricity flowing.

Back to the UPS - we got one and my computer has been very happy we did. It is an APC Back-UPS ES 450 and for a load of around 25w it has a reported run time of around an hour. It's not clear from the information I have seen what run time a load of 3.5w would have.



Anyway it is up for debate whether we will connect only one or both of the air pumps to the backup - connecting only one will require an additional power cable (as the UPS will be inside), connection of both will reduce power failure run times.