Natural control of pH and temperature levels for an aquaponics system

Abstract

Aquaponics is the combination of aquaculture (fish farming) and hydroponics (soil-less plant culture). Aquaponics answers the need for a sustainable food source with high production density considering the increasing human population. However, such system needs constant monitoring and proper intervention to maintain their productivity. The pH and temperature levels are crux parameters in a successful aquaponic system. The proposed method aims to control the pH and temperature levels naturally without the use of chemicals and synthetic materials that may affect health after consuming products from the aquaponic system. The closed-loop control system automatically checks and maintains the pH levels and temperature of nutrient -enriched water solutions used in aquaponics. Temperature and pH level sensors interfaced with a microcontroller regulate actuators and pumps for water circulation. Two circulating paths for water maintain the pH and temperature in the system: one that passes through a coral-filled container and the other passes through a collection of driftwood. Coral and driftwood served as controlling agents for lowering and raising the pH level of the water. Water cools down by stagnating for several hours in an insulated container. The pH and temperature measurements showed that the system was able to maintain desired levels. It took around 3.3 hours for the system to reach the target temperature, 19 hours to lower the pH level from an initial value of 7.7 to 6.5, and about 23 hours from 5.5 to 6.5. Controlling pH levels and temperature in an aquaponics system can be done using natural agents which impose no harm both to the fish and plants.