not so similar
8. temperature
An important part of an effective program to prevent pythium outbreaks in hydroponics is to make sure that the nutrient solution doesn’t get above 70°F. Warm water is a perfect breeding ground for fungus, so keeping the water temperature below optimal breeding conditions for pythium makes sense. In aquaponics, however, the primary drivers of temperature are the requirements of the fish. The most widely used fish in North American aquaponics (after goldfish) are tilapia, and tilapia does best in water that is between 74° and 80° F. The bacterium that drives the system is also happiest in that temperature range. Fortunately, pythium is so rare in aquaponics that it doesn’t present an issue. The plants don’t seem to mind either, as a 2005 report by Dr. Nick Savidov at the Crop Diversification Centre in Alberta, Canada, showed aquaponics is every bit as effective at growing plants as hydroponics.
9. ph
Optimal pH in a hydroponics system is 5.5 to 6.0. An aquaponics gardener must strike a pH compromise to meet the somewhat differing needs of the plants, fish and bacteria. Optimal pH is 6.8 to 7.0, which is again more closely related to what an organic soil gardener would target.
10. ec
Along with pH and water temperature, electrical conductivity (EC) is the other measure that is closely tracked in hydroponics. EC is a measurement of the salts in the nutrient reservoir that tells the
hydroponic gardener how concentrated the nutrient solution is. This works because hydroponic nutrients are generally found in mineral salt form. Aquaponic plants, on the other hand, are fed by the organic waste from the fish, which has very little salts. EC is therefore not a useful nutrient concentration measure in an aquaponics system. Aquaponics requires confidence in Mother Nature, rather than a managed system requiring intense control. Once a system has been constructed using a set of generally accepted rules of thumb and has been fully cycled (ammonia and nitrite levels have dropped to zero), the only measures an aquaponic gardener monitors are temperature, pH, ammonia and nitrates. If nitrates are low (close to zero), add more fish to the system. If nitrates are high (above 150) add more grow beds and/or plants. It’s as simple as that.
11. inSect control
Hydroponics
is a system for growing plants under highly optimized conditions. Aquaponics creates a complete ecosystem in which various living creatures all interact to create a symbiotic whole.”
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Maximum Yield USA | June 2013
You’ve probably guessed by now that since aquaponics is an organic system that uses fish, special care needs to be taken with regard to insect control. Even commonly used organic sprays such as insecticidal soap can be harmful if over-sprayed into the fish tank. On the plus side, you can engage your fish in your insect control efforts. If I have an insect problem on a small plant, such as young peppers or salad greens, I’ll remove them from the grow bed and let them soak in the fish tank for up to an hour. The bugs eventually loosen their grip on the plant and become fish food. And if you are lucky, the fish might even accelerate the process by nibbling the bugs directly off your plants. I also know of people who have hung Bug Zappers over their fish tank as an additional form of feed for their fish.