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

Abstract

The effects of natural zeolite as a bed medium in increasing lettuce and red tilapia growth as well as improvement of water quali ty parameters in an aquaponic system were investigated. An experiment with a completely randomized design was run with two treatments in triplicates, 1) an aquaponic syst em 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. Th e initial mean individual weight of red tila- pia juveniles was 6.23 ± 0.06 g and increased to 32.50 ± 2.00 and 37.50 ± 2.20 in treat- ments 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 concen- tration of total ammonia-N in th e 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 re- circulating aquaponic system could increase the growth of lettuce seedlings as well as im- proving water quality parameters.