John Colt

Aquaponics is the integration of aquaculture and hydroponics where nutrients released by growing fish are utilized by plants grown in a soilless culture, often in a controlled environment. Potential advantages of aquaponics include improved sustainability, reduced resource consumption, and fewer environmental impacts compared to conventional aquaculture. Based on a 2014 survey, it was found that most respondents were practicing aquaponics as a hobby. Other groups of respondents were educators, non-profit organizations that operate aquaponic systems, commercial operators, and consultants that sell goods, material, and services. Although many proponents cite the opportunity to create a commercially viable food production system few (if any) ventures have demonstrated sustainable financial outcomes. In general, much of the peer-reviewed aquaponic publications and popular literature, and despite the efforts of some investigators, lacks a methodical scientific basis for describing the essential mechanics, relationships, and culture methods within aquaponic systems. Many systems evolved from small-scale experimental facilities devised by trial and error methods and were implemented with locally limited appropriate species, limited finances, and distorted market situations. Many of the published aquaponic experiments are based on small systems, short growth trials, and weak experimental design. The predominant system design approach is based on a relatively small number of experiments. This review introduces notation and algorithms that are intended to standardize the numerous critical values essential in aquaponics for purposes of determining design criteria and operational parameters including flows, the concentration of water quality constituents, metabolite production, and productivity of plant and animal segments in an aquaponic systems. The objective of this systematic approach is to employ scientific methods that provide research results that can be replicated, challenged, and improved. This methodology is expected to facilitate more rapid development of scientific information, productive systems, and rational economic applications. This approach is crucial for commercial applications where production cost, product value, and investment returns are of critical importance for practitioners that envision investment in new ventures. For hobbyists and educators, economic issues may not be as important as the self-sufficiency and natural synergism aspects, personal satisfaction, and the learning experience that result from existing state-of-the-art of aquaponic practices. These outcomes remain for all and a clearer understanding of smaller personal systems is likely to be enhanced.

The impact of stirring on the response of the field YSI ProODO luminescence dissolved oxygen sensor was measured in a 300‐mL biological oxygen demand (BOD) test bottle with a magnetic stirrer either on or off. With a water sample from a fish transport experiment, the dissolved oxygen dropped by 2–3 mg/L when the magnetic stirrer was turned off for 11 min. The initial rate of dissolved oxygen decline ranged from −0.39 to −1.04 mg/L per min for this water. The dissolved oxygen returned to a value projected from the oxygen uptake rate when the stirrer was turned on. A much smaller impact was observed for 18.2 MΩ high‐purity water (mean: −0.11 mg/L). Acid‐washing the BOD bottle/stir bar and cleaning the sensor cap reduced the decrease to −0.08 mg/L. Based on t‐tests between pairs of stirring‐on and stirring‐off results, the lack of stirring had a significant effect on measured dissolved oxygen. The source of this effect and its potential impact on the accuracy of the optical probe under typical operating conditions remain to be determined.