Is an Aquaponics System Right for You?

Understanding the Basics of an Aquaponics Design

Is an Aquaponics System Right for You?

Joe Cadieux – I personally believe that this aquaponics system can save the world. No, really. Being able to produce multiple vegetable crops and high-quality protein in close quarters, all while reducing the total water needed for normal vegetable production, could assist greatly in the struggle for good, clean organic foods.

These systems can be purchased online where the manufacturers have sleuthed out a lot of the potential problems with setting up a backyard aquaponics system. They can be pricey, but they are proven systems and will save you a lot of time in setup and strategy.

This article is a brief primer for those of us who want to build an aquaponics system ourselves.

The science behind aquaculture/aquaponics is sound. Use the dissolved nutrients produced by fish to fertilize plants. Talk about efficient use of (potentially) scarce resources! These systems are scalable to just about any size. You’re only limited by the size of the water pump you want to use and space available for the project. I have seen aquaponics systems the size of your favorite living room recliner on up to warehouse-sized systems with multiple raceways raising several species of fish and crops.

What you need:

• Stock tank or other such water holding device to house your fish. Determine how big an area you’re willing to dedicate to this project and how many fish you want to raise to market size.

There is a rule of thumb: Five gallons of water per fish you want to raise.

• This is a loose number and it will vary depending on the species of fish you are raising and the temperature and water chemistry of the water (i.e. you’ll be able to raise twice as many Yellow Perch as Channel Catfish due to their relative size at harvest).

• The number of fish you can carry also depends on the filtering capacity of your plants. The more plants you have filtering the water, the more fish you can raise to maturity.

8′ round stock tank = 700 gallons of water = 140 fish

• Set up a plant table.

Planting tables need to be waterproof (I recommend rubber liner) and strong enough to hold up the weight of the plants and water running through the system.

• Your aquaponics design should have your plant table(s) at a height and width which are easy to reach across from a standing position. That way, harvesting and other maintenance is comfortable.

• Plant tables must pitch slightly towards the fish tank. The tables need to be constructed to contain whatever planting containers you choose (i.e. planting trays, pots, or similar planters) while allowing water to easily pass through the root zone.

aquaponics-system

• Plant your seedlings or plants with a minimum of soil. The object of this system is for the plants to take their nutrients from the water.

• Plumbing, pumps, aeration:

Plumbing consists of 1” PVC (or flex PVC) running to the higher end of planting tables.

• You must also make sure the water gets back into the tank. It’s most efficient to just position the table next to the tank and allow gravity to return the water for you.

• Size your water pump to the size of your operation.

• Small statuary pumps that pump 50-300 GPH (gallons per hour) are compact and economical to run, and provide more than enough flow for your plants. The moving water is also the main filtering device for your fishes’ water, so the more flow you use, the better filtration you obtain.

• A small but efficient aeration system is a must to keep your fish healthy and growing fast. Depending on the size of your tank (and number of fish), a good aeration system will cost $60-$250 and is easy to set up and run.

aquaponics-system
Red Tilapia

Now you need to pick out what species of fish to raise and what to grow on your plant table. When using aquaponics, fish species best suited to these systems are ones that don’t mind hanging out in a crowd.

• Rainbow/Brown Trout, Yellow Perch, Channel Catfish, Bluegills (or other sunfish), Black Crappie, Tilapia, and Goldfish are great species for an aquaponics system.

The above list is not exhaustive; there are a multitude of species you can choose from. I recommend selecting a species that is available in your area to reduce cost. If you live in a cold climate, knowing what are the best fish for a cold climate will be beneficial to you. You need to pick a fish species that can handle your climate (i.e. no Tilapia where it’s going to freeze in the winter, or no trout where water temps are over 75 degrees F).

Choosing plants for your aquaponics system is entirely up to you … Alas, root veggies are out of the question for obvious reasons (though I’m sure a stubborn engineer type could probably rig some way to make it work, and there are commercial systems available that are designed for just that purpose). Quick-growing crops work the best: lettuce, spinach, celery, etc. Other plants work well too. You just have to support the plants with a tower or other support to keep them upright: pole beans, tomatoes, cucumbers, squash, etc. The more robust plants will require a higher fish stocking rate to provide adequate nutrients to bring the veggies up to maturity.

This project is ambitious but can be a source of nutrition and science-y fun for a family that already enjoys working with plants and animals. I hope this intro into the world of aquaponics systems helps you to decide to take on an alternate form of food production at your homestead.

Please visit my website (Midwestponds.com) for more info on other pond-related topics. Feel free to contact me for advice on water-based issues.

Do you have an aquaponics system? What species of fish and how many do you raise? We’d love to hear your experiences!

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