Tutorial: Aquaponics 101
Getting into aquaponics can be a bit intimidating, so use this!
QUICK REFERENCE/SHOPPING LIST FOR MULTIPLE SYSTEM SIZES AT THE END
Aquaponics is a method of producing food that combines aquaculture (livestock like fish) and hydroponics (growing plants with water). The advantage of this is that we can produce a surprising amount of food in a relatively small footprint. The overall concept is also quite low maintenance once the system is actually setup and cycled for a bit. In essence, we are creating a small, self-contained ecosystem that provides what it needs on its own.
Remember, the concepts here are universal! You can design and build this any way you please. For instance, you can build a pond system for the fish, if desired. I covered this in depth in my other article, The Case for Aquaponics.
Structure
For our structure, we will be using what is called an IBC Tote. These are easily purchased used for $100-$150 (Craigslist is great for these). They come in a few sizes, but the most common is 275 gallon and thats what we will be using. Do make sure it is a food safe tote, and ask what was stored in it previously! These are typically referred to as “Single Trip.”
IBC Totes can also work really well for rainwater collection and are stackable. If you connect them together, with the outlet on the lowest tank providing water, you can even generate a good amount of pressure without the need for a pump.
Air Pump
For this system, we are looking at ~30lpm (liters per minute). We will also need some tubing to run it, and some type of diffuser to better oxygenate the water. There are a lot of options here, as well as kits, but I would suggest dishing out a bit of money on this. Its one of those things that will end up costing you more if you try to cheap out. Anything made by Supreme, Danner, Matala, Hakko, or in that realm of pumps will work great.
For everything though, we are looking at about $250 and the Matala MEA Pro 2 Plus kit would be my suggestion.
Water Pump
This moves the water from the livestock tank back up into the grow bed. These are generally pretty inexpensive, so it can be wise to always have a spare on hand. We really only need about 150gph (gallons per hour) in this rig, but with adjustable flow rates, head height, and expandability in mind, we can go a bit bigger. This 400gph Hydrofarm pump is a decent choice. And, they are not so expensive that getting an extra (or two) is cost prohibitive. Since we will be lifting our water about 3 feet, this 400gph will end up delivering about 250gph once installed.
Piping for this can be handled with good 'ol PVC.
Bell Siphon
Now that we have the pumps and structure sorted, we will need a Bell Siphon for the Flood & Drain system we are putting together. This will go in the middle of the grow bed (with the plants) and will drain the water back into the fish tank once it reaches a certain height. This isn’t a complicated piece, and we can DIY one out of PVC, but Smoky Mountain Aquaponics on eBay makes great stuff for a good price. For our system, we will look at the 12" siphon.
Grow Light
The last piece for year round growing is the grow light. These have come a very long way in the past few years, and while they still struggle to compete with natural sunlight, they can make a lot of installations work reliably regardless of conditions. That said, if you can build the structure containing your aquaponics system(s) to let in natural light, definitely do so! There are a lot of routes to take, but since we are also looking to have this backed up, or run completely on solar/wind/hydro, LED is the way to go.
This is an area where we can spend a lot of money, but its tough to beat these lights by Spider Farmer for cost efficiency. Lights like the Phyto-Max2 made by Black Dog LED are a great choice, but they also more than quadruple the cost of lighting alone. For LEDs, cooling isn’t as much of a concern, but a clip on fan getting some airflow helps.
Temperature Control
In the summer, keeping the tank cool is going to be our priority. However, the best ways to do this is through clever design or just simple evaporative cooling. With Tilapia, we are generally looking at 82F-86F, so we aren’t looking to keep it particularly cold. In the cooler months, this starts to require tank heaters as an easy solution, or even solar water heating for a bit more advanced solution. This will require roughly a 750w-1000w heater (about 5w per gallon, and we have ~175g tank) and having a bit of headroom is prudent if the outside temps really start to drop. With this much water, we have a good bank to store that thermal energy, but it can still get cold over time.
A heater like this one can help us ensure that it never gets cold long enough to become a concern. The Catalina RF-1000T is pretty standard for large tanks. A separate temp controller can be useful too, but that starts to get more complicated. If you wish to go that route though, you can get something like this Bayite Digital Temp Controller. There are also units like this Hygger 800w and this Hygger 500w. We want to try to hit that 1000w mark, but environment can change what we actually need a bit and we can also use separate, smaller units to get a bit more even heating.
I’ll be honest, I’ve yet to actually find a tank heater I liked (though I DO like that Bayite Temp Controller.. It’s handy). They tend to like to break, at any size tank. So make sure to have a spare! I wouldn’t worry about it right away, but keep it in mind. Just remember, we aren’t doing this so much as a hobby, but to provide supplemental sustenance for ourselves and our families.
Grow Media:
The last item we will need is a grow media. We will need a good amount too. Very roughly 15 cubic feet (112 gallons, 425 liters).
Yeah.. So that’s a thing.
One of the best is expanded clay, like Hydroton. However, if we add that up, we are increasing our cost dramatically. The best method I have come across is a layered approach. We put larger river rocks at the bottom (3/4"-1"), pea gravel to fill in the rest of the bulk, and then a final layer of expanded clay. The actual ratios are not hugely important, but try to make most of it pea gravel and expanded clay. I would suggest 100 liters of the Hydroton, and then go from there. We can purchase the pea gravel and river rocks online, but sourcing them locally is much cheaper (shipping costs!). Generally, we can pick this up locally for about $1 per gallon.
The only thing to watch out for, and this is important, is that the rocks/gravel have very, very limited amounts of limestone. Ideally none at all. Limestone will mess with our pH, and that’s a problem. We can test this by using vinegar; if it bubbles, we’ve got limestone.
I’d like to briefly mention a swirl filter. In a smaller system like this, we don’t really need to worry about it, but they are pretty easy to put together ourselves. We can also purchase them, and they can be made as decorative parts of the system, like waterfalls. Its a function over form type deal, but why not have both if we can?
Livestock
The general rule is 3-8 gallons per pound of fish. That’s a big range, but it’s dependent more on the bacteria colonies and the growbed being able to handle the nitrification process. We can technically raise any fish we want, but since the goal of this system is year round production for supplementing a family, we will be looking at Tilapia and freshwater Shrimp/Prawns.
They both like the same temp regions, the same pH regions, tend to get along well (enough), and can grow to the harvest point quite quickly. For fish, we usually look at the 1 pound mark and for Tilapia, that takes a bit over 6 months. The shrimps/prawns take 4-6 months.
We aren’t looking at a whole lot of prawns, less than half a dozen. It might even be better to look at them as tank cleaners more than an actual food source. Breeding can happen and for higher chances of success, a prawn hatchery can be built.
The temp range for Tilapia is going to be 82F-86F (28C-30C) and they like a pH range of 6.5-9. General freshwater shrimp & prawns will thrive in ~60F-84F (~15C-29C) and a pH range of 6.5-8. That means we want to keep our system at 82F-84F and 6.5-8 pH. We can actually go outside these ranges, by more than one might imagine.. but not for too long.
To keep this in check, as well as keep our eyes on things like nitrites and nitrates, its best to get a testing kit like the industry standard API Master Test Kit. Products like pH Up & Down can be useful too. We probably won’t be using the pH Up & Down, but it is good to have around. As opposed to normal aquariums, or normal hydroponics, the system should take care of itself beyond that!
As a guideline, we are looking at about 100ft² (~9.5m²) to produce about 1lb (0.5kg) of protein a day. That’s amazing, if you really think about it! Obviously, it still takes up room, and that can add up pretty quick if we are looking to feed a large family. But its tough to deny the advantages of being able to provide your family with food, year-round.
Crops
Crops are a massive topic all their own. Generally speaking, crops like corn will not do great because of their height. Its doable, just requires special consideration. Likewise, anything that grows a lot of roots very quickly can be difficult to deal with. Crops like potatoes aren’t a good choice either, but they can be grown in a Tater Box.
Other than that, there really aren’t too many limits other than creativity and how much time you want to put into it!
A crop like strawberries can do great, but they can require a lot of plants to actually have meaningful yields. With that in mind, I would personally recommend some nice leafy greens like a Kale, and trying to fit some medicinal plants like artemesia annua in there too. Having a germination chamber can help a lot as well.
Construction:
Now we get to the actual construction. Ill only give some general guidelines here. There are no steadfast rules. 1" PVC is your friend, and is a wonderful construction material in general. You want to avoid too much metal, as it can mess with the pH, but a little here and there isn’t a big deal, particularly in areas that do not come into contact with water.
To create a tank and a growbed from the IBC Tote, we have to cut it. Its easiest to separate the inner plastic from the outer metal cage for this process. To create the growbed, we are going to measure down 14" from the top of the plastic tank and cut all the way around. We will do the same for the outer cage so that both the growbed and tank have the support from the cage. Don’t worry too much about precision, unless your OCD will bother you later on..
We want to set it up so that the water cycles from the livestock tank to the growbed and back again. The simplest way to do this is to place the growbed directly on top of the tank. This can be done anyway you want, but make absolutely certain that whatever you build can support the growbed with media, plants. and water! It can also be a good idea to make a cutout on the front top of the tank so we can access the fish & prawns easily.
The bell siphon is easiest to install right in the middle of the growbed. This will just drain directly into the fish tank. A lot like the drain in a bath tub or shower. Then, to get the water back up, we need to run tubing from the submersible pump in the tank so that it will pour out into the growbed. This can be done with PVC quite easily, and the easiest would just be a single pipe running from the water pump vertically to a 90 degree fitting that pours it into the growbed. Aquarium tubing can work as well. Fittings, and various bits and pieces may put the project on hold while you make it so it doesn’t leak. Don’t be surprised by that!
Our air pump goes near the livestock tank, and will pretty much work anywhere we put it. We will then run the weighted hose from the kit to the air diffuser we place into the tank. However, if we are going to make life a bit easier on the fish through things like structures and objects (which can also help the prawns/shrimp hide, the younger fish run around, etc), we need to make sure that wherever it goes isn’t obstructed.
Our heater can technically go anywhere, but to produce as even temps as possible, we should place it somewhere that will circulate the most, but also in a spot where the fish do not have easy access. Because we are dealing with a (roughly) square tank, this presents a bit of a challenge. However, we can divert some water from the water pump, or air from the air pump, to move the water however we wish.
Now we just place the media in the growbed in whatever fashion we desire, filling it up about 12". The idea isn’t to completely submerge the media, so keep that in mind. We want an inch or two of the top of the media that stays dry to prevent the growth of algae, etc. There are other ways to achieve this too, but the most straightforward is to leave the top portion dry.
Getting it all going:
Now, before we really get going, it is a good idea to try to run the system to rinse the media. We can even build a little PVC pipe system that runs where the bell siphon would be, then rinse the media with a hose in the grow bed before we construct the system, use sieves, etc. The idea is to wash away as much debris as possible.
Once we have our media in place and clean, we can start the beginning stages of cycling the system. What we want to achieve here is a thriving ecosystem of everything from plants and fish, to bacteria (called a biofilter). This can take a while to achieve (a few weeks), and there are no hard and fast rules. Letting the system run for a few days without any crops or fish is wise though; we want any residual stuff from the media to dissipate, as well as any chlorine or other chemicals if we have used tap water to fill the system. We can use the API test kit to get a read on progress.
The cycle of our ecosystem is that the fish waste creates ammonia, which is converted to nitrite by bacteria, and the nitrites are converted to nitrates by other bacteria (nitrification). We want the nitrates to feed the plants. Once we have the base going, it’s time to add some fish to really get that nitrification going. It doesn’t take many at this stage. I’ve even known some to use goldfish to kickstart things, as they are very hardy, or adding bacteria colony starters directly.
We will be checking ammonia, nitrites, and pH levels until they get where we want them. We can expect to see a lot of fluctuations, but when all is said and done, the bacteria colonies handling the ammonia and nitrites should keep those levels ultra low, and the plants should be taking care of the nitrates. Nitrates aren’t as much of a concern, but it can be a good idea to watch them all the same. In fact, once our system is healthy and has been healthy for a month or two, nitrates will be the one we test most frequently!
If the system is producing too much nitrates for the plants to take in, the issues are not always as apparent as if the nitrite or ammonia levels are high. When we test for nitrates, we want to see a bit over zero, but not higher than 20ppm. If it reads zero, that means the plants could probably use more nitrates. Adjusting that can be done in a lot of ways, but it all goes back to fish poo and bacteria biofilters.
If we have an established, healthy system.. a lot can be adjusted simply by how much we feed our fish. We can also adjust it at the other end by changing how many plants are in our grow bed.
Quick Reference
Aquaponics System: $958 (Not including crops/fish and can certainly change over time!)
Structure:
IBC Tote (Craigslist): $100-$150
Air Pump & Fixins:
Matala MEA Pro 2 Plus: $250
Water Pump:
Hydrofarm 400gph: $30
Bell Siphon:
Grow Light:
Spider Farmer SF-1000: $160
Heater:
Hygger 800w: $70
Grow Media:
Hydroton 50L x2: $89x2=$178
Pea Gravel/River Rock (local): 80g at $1/g= $80
Testing:
API Master Test Kit: $30
pH Up & Down: $20
Crops & Livestock
No links.. But you can actually get Tilapia fry on places like eBay. Its not as crazy as it sounds! Water isn’t compressible, and if the seller is good, they will pack it in an insulated bag to make sure temps stay stable.
For crops, we can look at either seeds or starter plants. Small plantlings will be quickest and "easiest," but also cost more. Seeds are less expensive and can be stored, but take more time and effort. When getting started, its not a bad plan to jump right to lil plantlings and then have seeds on hand. For seeds, a germination station can be quite useful.