The Easy Off-Grid Way To Start An Aquaponics System

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There is an abundance of information on the Internet describing how to set up an aquaponics system, and a lot of that information makes it look frighteningly complicated and time-consuming. Today, I am going to try and simplify it for you, and hopefully make it less scary.

So what’s aquaponics? It’s a combination of fish and plant production using aquaculture and hydroponics systems. But is it really as easy as I claim?

This is a yes and no question. Yes, because it can be as easy as you want to make it. And no, because both aquaculture and hydroponics have difficulties inherent in the systems. When combining the two systems you can reduce the difficulties to just a few rather than a few dozen.

The difficulties you can run into with aquaponics are few and can be remedied fairly easily. These problems are:

 

1. Space

Where can you put your fish tank and grow beds? Solutions:

• Any south-facing space just like a greenhouse.
• A basement, garage or carport. If you use an enclosed space like a garage or basement you will need to invest in grow lights since sunshine and heat are essential for both fish and plants.
• A greenhouse. This is the absolute best place for an aquaponics system since you won’t need to provide a heater for the fish tank in cold weather.

 

2. Equipment

Solutions:

• If you don’t have access to food-grade containers you can line the containers you do have with pond liner.
• DO NOT use any containers that have been used to store chemicals or are comprised of any metal other than stainless steel. Avoid anything copper so that it doesn’t leech into your system since it can poison your fish.
• Any food-grade plastic containers large enough to hold 10-20 fish for a small system will work.

 

3. Time

Solutions:

• An aquaponics system is not usable as soon as it is assembled. You will need to develop your bacteria colony before you can stock the fish tank and wait till you see how your fish are doing before planting your crops.
• It can take anywhere from 10 days to 3 weeks to allow the bacteria to find your system and develop a colony that will benefit your plants and fish.

Setting up your system is easy once you have the space you want to build it in. For this article, we will be concentrating on setting up your system inside a greenhouse.

Here’s the equipment you’ll need:

 

Fish Tank

• This can be a large fish aquarium, a vinyl kiddie pool or any food-grade plastic container.
• You will want to figure about 10 gallons of water to each fish. The ratio is 1 pound of adult fish to about 10 gallons of water. Stocking your tank with one fish per 10 gallons of water will help to keep your system balanced and reduce the amount of ammonia in the water and keep the pH in the optimum range.

 

Growing Medium

• Most DIYers setting up an aquaponics system will use pea gravel. It is relatively inexpensive and easily acquired.
• You can also use coir, peat moss, or expanded clay pellets.

 

Grow Beds

• These can be any other food-grade containers that you have access to. They should be between 6-12 inches deep although the deeper containers will allow you to grow a more varied number of plants in each bed if you are working with a limited amount of space.
• Many people will simply build a grow bed and line it with pond liner. Doing this allows you to make it to the size you want and you can choose to stack grow beds for more planting space and add legs so that it will fit over your fish tank.

 

Freshwater Master Test Kit

• A test kit is necessary to keep control of the chemicals that can build up in your fish tank. If there is too much ammonia in the water or the pH is too high it can harm your fish. If ammonia is high in the tank then your beneficial bacteria aren’t getting the nitrites they need to live and the plants aren’t getting the nitrates the bacteria produce.
• These kits test freshwater pH, ammonia, nitrite, high range pH and nitrate levels to help you control those levels more easily.

 

Water Pumps

• I am going to assume that you will be using an intermittent flow system since it is the easiest to set up and operate. However, you can also use either the continuous flow or ebb & flow systems as well.
• Choosing a water pump is very important for “turning over the water.” This filters and aerates it so that your fish remain healthy and the water does not become toxic with the amount of ammonia contained in suspension.
• An intermittent flow system means that the grow beds will be flooded once an hour in a 15 minute on and 45 minute off cycle.
• Things to consider when choosing the right pump are fish tank volume and the distance between your pump and the top of your grow bed where the water will flood the growing medium. We will have to make a lot of assumptions here. Your calculations and measurements may be different from this picture we are creating.
  • Assumption No. 1: Your fish tank is 100 gallons. One-hundred gallons divided by 24 hours means you will want to move 4-5 gallons per hour. However, you will not want to get a pump based solely on that figure.
  • Assumption No. 2: Your fish tank is 2.5 feet deep and your pump will be sitting 6 inches from the bottom. Elevating your pump means you won’t get a bunch of solid fish poo gumming up your pump.
  • Assumption No. 3: There are about 1.5 feet between the top of your fish tank and the bottom of your grow bed.
  • Assumption No. 4: Your grow bed is 12 inches deep.
  • With these four assumptions made, we can determine what size pump you will need to purchase for your system. Simple math skills will aid you here. 30 inches (fish tank depth) – 6 inches (pump elevation) + 18 inches (space between tank and bottom of grow bed) + 12 inches (grow bed depth) = 54 inches. This means that your head height, or the distance between the pump and the top of the grow bed, is 4.5 feet.
• The best pump to get for the system described will be one that will cycle 5 gallons or more per hour with a head height (or “rise”) of about 5 feet. You will also need to consider the size of tubing that you are using for your pump. There may be an efficiency loss of 15-30 percent the greater your head height and tubing size are.

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What Fish Should I Use To Stock My Tank?

What type of fish you use depends on one of two things. Are you going to eat them or are you just raising them for the poop? My answer is that I intend to eat them so I’m going to list the fish that are often stocked in aquaponics systems.

 

Tilapia

• These are the most common fish stocked in aquaponics systems. They are the most common because they are herbivorous fish and won’t eat each other as they are growing.
• Tilapia love warm waters, so an aquaponics tank in the greenhouse is perfect for them.
• If your tank is in optimum working order, the fish will reach harvestable size in 4 months.
• They are more resilient in less than optimum tank conditions.
• They can be stocked in higher densities than most fish. This means you could get away with 1 fish for every 5 gallons of water instead of 1 per 10.
• They love to eat plants and duckweed, so if you can get duckweed to grow on top of your tank you’ll only need to feed them supplemental pellets.

 

Catfish

• These fish are a bit more finicky than Tilapia but still work well in an aquaponics tank in a greenhouse.
• They are resistant to both disease and parasites in properly controlled water conditions.
• They are bottom dwellers, so they are a low yield food fish. Many people add bluegill to the catfish tank since the bluegill will occupy the upper level of your tank while the catfish occupy the bottom. This increases your yield at harvest time.

 

Bluegill

• This is an omnivorous fish. They like to feed on small crustaceans, worms, insects, plants and even smaller fish.
• They are a fairly sturdy fish and are similar to catfish in that they do very well so long as you properly control the nitrate and pH levels in your tank.

Other fresh aquatic critters you can use in aquaponics once you have the technique down are crawfish/crayfish, freshwater mussels, and freshwater prawns.

 

What Plants Can I Raise In My Grow Beds?

Any plant that can be harvested as a leaf will grow well with just the fish providing the nutrients the plants need to grow: leaf lettuce, kale, basil, spinach, arugula, dill, chives, etc. This is a benefit to your winter produce since you’ll be able to enjoy fresh salads all through the cold months.

Strawberries, raspberries, blueberries, tomatoes, zucchini, cucumbers and other plants of this nature can also be grown in your aquaponics system. However, you will need to find a supplier for the supplemental fertilizer you will need to add for them to grow properly. Any plant that flowers to produce a fruit needs boron, copper, sulfur, and other nutrients and minerals to fruit properly.

Unfortunately, you will not be able to grow any plants where the harvestable product is grown at the roots. This means you will need to grow your potatoes, sweet potatoes, beets, carrots, parsnips, radishes and turnips in dirt. But since you are setting up your aquaponics system in your greenhouse, this is a benefit because now you can use those places that would be taken up by your leaf crops to grow more root crops. And you’ll get about 30 pounds of harvested, edible fish per year if you use tilapia.

 

Final Thoughts

I cannot stress it enough: Always do your research before adding to your aquaponics system. Make sure that you have the space, materials, time and energy.

One thing I have not talked about in this article is breeding space for your fish. If you don’t want to have to purchase fingerlings every few months and wait for them to grow up, you will need to provide breeding space within your tank or a separate tank for your chosen breeding pair so that the grown fish don’t attack the resulting fry. Again, you will need to research what your species of fish requires for breeding and what the fry require to grow into fingerlings.

Remember that when you harvest your fish you will get roe from them. Roe from the males can be fried up for dinner or sold as fish bait while the roe from females can be rinsed, salted and cured into your very own caviar, which can then be canned and kept to surprise your friends and family with a “posh” treat on special occasions. Depending upon the species and sub-species of your fish, the color of the roe will be nearly any color between creamy yellow and dark purplish-red.

I’m sure that there are a few other things you may want to know, but all I can offer right now is to do your due diligence and research everything. Happy harvesting!

Do you have experience with aquaponics? What advice would you add? Share it in the comments section below: