What are the common problems with aquaponics?
Text: Gogreen.tw Lin Kun-yao / Huang Chang-li
Q: Does aquaponics need nutrient solution added?
A: First define what the nutrient solution consists of. If you mean the nutrient solution used in hydroponics, then no.
Q: If other substances need to be added, how can they be added naturally and safely?
A: Based on UVI research, leafy greens generally may need added iron, calcium and potassium. In practical
terms, my balcony aquaponics system only had chelated iron added once when it was first set up. Afterwards no
iron deficiency ever appeared again. The reason may be because of the media bed, and because earthworms were
also kept in the media bed. At the same time, during the roughly two and a half years after setup, the pH was never adjusted. It was only in the third year that I used calcium carbonate to adjust
it.
Based on the current experience of the Linkou Aquaponics Family Farm, because the system is large and uses raft beds, chelated iron is added from time to time.
For pH, calcium carbonate (occasionally potassium carbonate) is used to raise it. UVI's recommendation is to add 2 mg of iron per 1 liter of water. For DTPA chelated iron, the iron content is 11%, which converts to about 18 grams added per ton of water. Add once every three weeks. For systems not focused on quantitative output, visual inspection can be used (that is, deciding whether to add by visual inspection), adding only when iron deficiency is found.
For aquaponics enthusiasts with home systems, I suggest adding chelated iron once when the system is first set up; after
that, visual inspection can be used, adding only when iron deficiency occurs. The way to judge is whether old leaves are normal in color, whether new
leaves are yellowish, and whether plant growth is slow. As for chelated iron, some countries have organic certification for it, but
Taiwan, China currently seems to have no such certification.
As for calcium, if enthusiasts want to add it, I suggest using crushed oyster shells; some people suggest using coral
stone, but I personally do not recommend it, because mining coral stone damages the environment. As for potassium,
I once dried banana peels in the sun and placed them at the water inlet of the grow bed, but I cannot be sure whether my balcony system was ever deficient in
potassium.
Q: What are your future plans?
A: I hope to work with industry, government and academia to jointly promote standardization and a certification system for aquaponics, so that aquaponics can develop in a sound
and healthy direction and become a truly large-scale production industry.
Note: Huang Chen-wei is another aquaponics enthusiast; see the other report.
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