Aquaponics is a very intelligent idea. But it’s also ugly – pipes going every which way, around large growing containers. I want one but I want one that looks good. I’m dreaming of a system that resembles an upscale outdoor water feature. I have not found a design to buy that I like. I’m gonna build one.
Don’t confuse hydroponics with aquaponics. Aquaponics is a system of simultaneously growing plants and fish: Fish fertilize the water with waste product. The nutrient water is then pumped to feed the plants. The plants in turn, filter the water and the clean water is returned to the fish. This is a closed system requiring a water tank for fish and growing beds for plants so that every aspect can be controlled.
FISH. The most popular fish for aquaponics is the tilapia. They grow fast and are tolerant of neglect. They are disease resistant, with a mild flavored, white flesh. Because of their tolerance for poor water quality and crowding, tilapias are well suited to recirculation systems. They eat dry cat food and algae. Fish are ready to harvest at about 1.5 lbs, in about 6 months. My husband and I, eating fish twice a week, would need to harvest 72 tilapia over 6 months. I plan for 1/3 of the population to be “fingerlings,” (slightly larger than a minnow) 1/3 to be juveniles and 1/3 to be adults, ready for immediate harvest.
WATER. Tilapia growth performance is best in a water temperature range of 72-90º F. Growth slows in water temps below 70º F. They are intolerant to cold and will die when water temps dip below 45º F. In most geographical areas, raising tilapia outdoors without a way to control water temp is a seasonal endeavor. A healthy system will plan 3 gallons of water for each pound of fish. My fish population will be at different sizes and weights thru the 6 months, but for planning purposes, I’m planning for 58 lbs of fish, requiring 178 gallons of water. Water weighs 8.3 lbs. per gallon. My water tank will weigh 1,442 lbs. Planning a solid, level base will be important.
DIMENSIONS. 1 cubic foot (cf) of space is 12” wide, 12” long and 12” deep. 1 CF holds 7.48 gallons. Thus my tank, holding 178 gallons will require about 23.2CF. I am planning a tank 6’ long x 2’ wide x 2’ tall – 24CF
GROW BEDS. The key to success in an aquaponics system is in managing plants: too many and there won’t be enough fish waste to feed them all; too few and there won’t be enough plants to filter the water. As the fish population grow and fatten, the need for plants will increase. Thus flexibility is necessary. I’m planning a growing space 6’ long, 2’ wide and 1’ deep. If I need more plants, I’ll set up vertical growing space overhead. I chose a growing medium called “expanded clay pebbles” – it takes the place of soil, giving the roots something to hold onto. Clay pebbles don’t rot and are not susceptible to fungus. Thus you can reuse them year-after-year. Also, they weigh much less than gravel which means the grow bed construction needn’t be robust.
PLANTS. Any shallow-root plant can be grown. Strawberries, herbs, lettuces and other leafy veggies do well. Flowers and ornamentals also do well. Stay away from deep rooted tomatoes, cucumbers, melons, as well as root-plants such as potatoes, peanuts, large carrots and the like. Start the plants first to get them growing, then add fish.
THE PLAN. The plan is to incorporate this information into a functional system that resembles a water feature, worthy of my upscale suburban backyard. As you can see from the Google SketchUp, I’m planning the growing bed to be positioned over the fish tank. However, the center section of the grow bed is elevated, allowing for water to cascade into the lower beds – thus the delightful sound of a splashing water feature. A 12” area between the fish tank and the grow bed allows room to feed and harvest fish.
THE MATERIALS. I purchased a used equine watering-trough purchased from the Re-Store, it’s a near-perfect size and a lucky find. (This is KY, you know.) I also found 3 over-sized, plastic bus trays in the kitchen area of Sam’s Club. They should work well for the grow beds. I’ll use 1” PVC to support the grow beds and ¾” PVC for the plumbing. I plan to enclose it all on three sides with interlocking concrete blocks from Home Depot. The upper blocks will be supported by a piece of metal. The back will be hidden by a large shrub but open, for possible maintenance. My hope is that it will look like a stone water fountain.
With the addition of a pump and a few other accessories, I expect to spend just shy of $200 on this project.
It may not be the aquaponics dream setup for everyone. Sure you could buy a plastic barrel and cut it in half – if that fits with your landscaping motif. But for me, it’s a perfect fit for my family and I am very excited. To learn more about building a DIY aquaponics system, search YouTube. Happy fishing!