The Effect of Natural Zeolite (Clinoptiolite) on Aquaponic Production of Red Tilapia (Oreochromis sp.) and Lettuce (Lac-tuca sativa var. longifolia), and Improvement of Water Quality.

The effects of natural zeolite as a bed medium in increasing lettuce and red tilapia growth as well as improvement of water quality parameters in an aquaponic system were investigated. an experiment with a completely randomized design was run with two treatments in triplicates, 1) an aquaponic system without use of zeolite as a control group and 2) use of a small cotton bag, containing 10 g zeolite as a bed medium for planting a lettuce seedling. in each experimental unit, 42 seedlings of lettuce were introduced. the individual weight of fish and lettuce yield in treatment 2 was significantly higher (p< 0.05) than treatment 1 at the end of experiment. the initial mean individual weight of red tilapia juveniles was 6.23 ± 0.06 g and increased to 32.50 ± 2.00 and 37.50 ± 2.20 in treatments 1 and 2, respectively by the end of experiment. the yield of lettuce was higher in treatment 2 (1507 ± 445.00 g/unit) compared to the control (275 ± 83 g/unit). the concentration of total ammonia-n in the water was significantly lower (p< 0.05) in treatment 2 compared to treatment 1 at the end of experiment. the concentration of phosphorous and potassium in the fish rearing tanks was significantly lower (p< 0.05) in treatment 2. these results indicated that the use of zeolite, as a bed medium to plant lettuce seedlings in a recirculating aquaponic system could increase the growth of lettuce seedlings as well as improving water quality parameters.