Growth performance of Nile tilapia, Oreochromis niloticus, fingerlings reared in Na2CO3 limed waters

Current experiment was undertaken during 6 weeks with Nile tilapia, Oreochomis niloticus, fingerlings (1.28 ± 0.03 g) to assess the effects of moderate Na2CO3 liming on water quality and fish growth performance. Twenty-four 25 L-aquaria, with 15 fish per aquarium, were used, of which twelve aquaria were placed in the lab’s indoor room and twelve in the outdoor area. Two types of water (clear or green) and three different water-quality managements (none, HCl acidification and Na2CO3 liming) were simultaneously evaluated in a 3 x 2 factorial design. Total ammonia, calcium hardness, pH and total alkalinity in the green water aquaria were significantly higher than rates in the clear water aquaria. Slight liming acid water with Na2CO3 did not produce any significant effect on its water calcium hardness. No significant differences between controls and the experimental group were observed for any growth variables. Lime rearing water Na2CO3 has no significant effect on tilapia growth performance if the initial total alkalinity of water is higher than 20 mg CaCO3 L-1.