The SPACE 200 (Sustainable Probiotic Aquaponics Cultivation Environment, 200 gallons) is an aquaponics system built by Galactic Farms that has been operating at the University of Montana Dining Services (UMDS) since 2015. The SPACE 200 uses an agricultural technique called aquaponics, where fish effluent supplies all the nutrients that plants regularly obtain from the soil. This technique for food production is somewhat complex and requires an understanding basic chemistry and the biology of the living components (fish, plants, and probiotic bacteria). Thousands of students see this system every day and it is our hope that this exposure to aquaponics gets the next generation thinking about the role of nutrient cycling in food production. In fact, it has already inspired students to build their own systems at home.
January 2015
May 2015
SPACE 200 October 2016 – On FLEEK!!!!
How the SPACE 200 Came to Be
UMDS is committed to sourcing local food for the University of Montana cafeterias. They have many gardens on campus that produce fresh produce for the students, but they wanted to expand to year round production. Their hopes were to implement a system that would be mobile, have a small footprint, and be displayed in the university dining hall year round. Jeff had previously worked with UMDS to build an aquaponics mircogreens demonstration system for an independent study program he created through the Department of Environmental Studies. UMDS asked him to pitch a system that would fit their needs so he suggested a controlled environment aquaponics system. This type of system makes year round production possible so local sourcing of veggies can continue in every season. A known issue faced when building a system like this is the initial unpredictability while environmental fluctuations settle down. Also, using supplemental grow lighting during the winter can be energetically expensive. Luckily, energy is relatively inexpensive in Western Montana because 56% is supplied by renewable sources like wind and hydroelectric.
Building the system was a lot of fun for Jeff. He took his UMDS proposal to his engineering buddies Chuck Gailey and Troy Letisko to see what they could do with his initial plans. They made some adjustments that made the system seismically stable (i.e. wont crush people if there is an earthquake) but kept the system mobile. Jeff also realized that he needed to sacrifice productivity for design because the project is intended for educational purposes. Normally, fishtanks in aquaponics systems wouldn’t be exposed to light to prevent algae growth. However, it is important that students are able to see the fish because they are the source of nutrients for the plants and making this realization about nutrient cycling is really the main purpose for creating the educational display.
For plant media he chose to use Zip Grow towers from Bright Agrotech. He liked the look and simplicity of the towers and thought they were perfect for an educational display. They show how vertical space can be used for plant cultivation, which tickled us because our mission at Galactic Farms is to grown food in the least expected places. The Bright Agrotech team has been amazing to work with. They check up on us regularly and are always on hand to offer support and expertise on aquaponics and hydroponics growing systems.
After the system was built, we needed to inoculate the water with beneficial bacteria and the fish that carry them. We sourced fish from the Frenchtown pond after obtaining a fish transportation permit. Fishing in the winter was “fun”; we got all bundled up, drilled holes in the ice, and sat out there for hours. We caught about one perch or so a week until one day in early spring when we caught 20 perch all at once.
As mentioned previously, aquaponics systems do require some intelligent and informed maintenance on the part of the gardener. We found that for our situation, the best plants to grow were basil and chard. We ran into a few issues over the course of time we have been in operation. Below is a diagram of these issues and what we did to manage them:
Problem |
Solution |
| Hard water | Water in the Missoula area has a lot of minerals that cause the pH to be higher than the pH where plants can uptake most nutrients. Normally, the best thing to do in this situation is use a reverse osmosis machine to remove the buffering salts from solution but the UMDS did not have the funding for a reverse osmosis machine. Another solution we have been using for our home demo system is to dilute the hard tap water with rainwater. The university is interested in implementing rainwater catchment, but it was not available to us quite yet. So in place of a better solution, we have been limping along measuring and adjusting the pH, and carefully adding small amounts of muriatic acid to bring the pH down to a level where plants can absorb the nutrients in the water. It is important to do this slowly because too much acid can kill the probiotic bacteria responsible for making nutrients available to plants. We really struggled because hard water salts were precipitated on the edges of the mixing tank and when we added the acid they would dissolve into the solution, raising the pH again. Buffers are a b*tch.
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| Cholorosis
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 Because of the hard water, the plants had difficulty absorbing many nutrients. This made them look yellow, aka “chlorotic.” The pattern of yellowing and dying plant tissues can be informative about the particular nutrient that the plants are struggling to obtain. We experimented with giving them supplementary chelated iron and zinc, and potassium. They reacted favorably to these additions, but some of the nutrients we added probably were precipitating out because the pH was still too high for them to be in high concentration in the water solution.
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| Dripping | The media towers that the plants grow from are a really great product, but they do tend to leak on the floor, which is a safety hazard in a public space. This was easily remedied by leaning the towers at a slight angle and pruning the lower leaves on the plants when they got really bushy.
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| Too much nitrogen | Because of the hard water issues, nitrogen uptake was slow for a period of time. The high nitrate concentration in the water was stressful on the fish and some of them died. We changed the water to dilute the nitrogen buildup, but the water that we added needed to be pH adjusted first.
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| Aphids | Aphids appeared because outdoor plants were transplanted into the indoor system. This is a common occurrence in controlled environment systems; something that was kept at low levels in a complex garden ecosystem becomes a pest when brought into the more simplified controlled environment ecosystem. In our home demo system, we introduced ladybugs to bring down aphid numbers, but because this was in the school cafeteria that did not seem like a reasonable solution. We were not about to have a bunch of ladybugs flying around the cafeteria, laying their eggs, and dying on people’s california rolls. Currently the garden managers are hand squishing the aphids and this works alright for now.
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