Growth of Gynura procumbens and oreochromis spp. by using cocopeat media in aquaponics system

Lightweight expanded clay aggregate (LECA) and gravel are common growing media that are used to support plants in hydroponic system. However, LECA is quite expensive and gravel causes the presence of algae. Therefore, alternative media from local source are required. The study evaluates the growth rate of Gynura procumbens plants by using four different growing media (LECA, cocopeat, rice husk and mixture of cocopeat with rice husk) in an aquaponic system. The media were analysed based on the physical and chemical properties before being used as growing media in the aquaponics system for water quality, nutrients level and growth of Gynura procumbens plants and Hybrid red Nile Tilapia fish. Results attained signified the suitability of utilizing rice husk and cocopeat as alternative media compared to commercial media such as LECA because there was a significant difference (P< 0.05) between all analytical tests. Commercial media such as LECA did not require water treatment unit but the usage of cocopeat is not guaranteed by its effectiveness in treated water in the aquaponics system. Therefore, extra filtration system (single or combined) filter was required and the study of four different water treatment units (mechanical, biological, combination and media) by using cocopeat as media in the aquaponics system. The water treatment unit was being compared based on water quality, nutrients level and growth of plants and fish. All the aquaponics systems were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level measured to be within the range of 6.4-6.9 (± 0.07), 27.7-29.0°C, and 5.5-7.0mg/L (± 0.09), respectively. Satisfactory reduction (50-70%) was achieved for total suspended solids (TSS) and the nitrogen compounds within the systems. The results revealed that cocopeat was insufficient to act as a water treatment unit in the aquaponics system studied. The aquaponics system required at least a biological or mechanical filter for effectiveness in treating water of the system

Carbonized rice husk and cocopeat as alternative media bed for aquaponic system

The study evaluates the suitability of carbonized rice husk and cocopeat substrates as alternative media bed in aquaponics unit for cultivation of red Nile tilapia and Gynura procumbens. Area occupied by the aquaponics unit is about 4.5 m2 and it was operated under equatorial climate conditions. Various substrates namely lightweight expanded clay aggregate (LECA), cocopeat, carbonized rice husk and a mixture of cocopeat-rice husk at ratio 1:1 were prepared using polybags for growing of the longevity spinach. The resultant effects from fish cultivation and plants growth on the water qualities and nitrification efficiency of the aquaponics unit were reported. The aquaponics unit were operated for twelve weeks and the values of pH, temperature, and dissolved oxygen level were measured to be within the range of 6.4-6.9, 27.7-29oC, and 5.5-7 mg·L-1, respectively. Survival rate for fish was 98% with specific growth rate (SGR) and food conversion ratio (FCR) of 6.9% per day and 1.13, respectively. Nutrient deficiency was not evident and plants showed healthy growth with harvest yield ranging between 3.6 and 3.9 kg·m-2. Results attained signified the suitability of utilizing carbonized rice husk and cocopeat as alternatives media bed compared to commercial media bed such as LECA