The experiment was conducted at Directorate for Sustainable Aquaculture Thanjavur (10° 47’ 13.1964’’ N and 79° 8’ 16.1700’’ E), Tamil Nadu Dr. J. Jayalalithaa Fisheries University, for a period of two month from 10th April 2019 to 10th June 2019. Six cemented tanks of 35 liter capacity filled with pond water were used to carry out the experiment. To increase the ammonia level the dose of urea and cow dung was calculated (0.5 gram and 50 gram respectively) for 35 liter water and applied in all the selected water tanks equally. Three treatments (T1, T2, and T3) and two replications (R1 and R2) for each treatment were performed. 5 gm dose of CaCO3 for T1R1, T1R2, 10 gram for T2R1, T2R2 and 15 gram for T3R1, T3R2 were used to correct the ammonia level. The maximum ammonia and pH level observed were 1.7 ± 0.670 mg/ltr and 8.395± 0.12 respectively in tank number T2R1 while the minimum dissolved oxygen level was found 1.5 ± 0.712 mg/ltr in the same tank. The nitrite and nitrate level were remained below detectable levels in all tanks. The maximum suitable dose of CaCO3 was calculated at 1428.57 Kg/ Hectare. Ammonia decreased with increasing lime concentration in the medium. It could be concluded that Liming affected positively and directly organic matter decomposition accumulated in the sediment. This is extremely important, since high concentrations of organic matter in the sediment may result in anaerobic conditions at the soil-water interface which can lead to production of obnoxious gases.
Key words: Ammonia, Calcium carbonate, Cow dung, Urea, Pond water.