Litopenaeus vannamei (the Pacific white shrimp) is the most commonly reared species in super-intensive bio-
floc technology (BFT) without water renewal. In BFT, the pH may decrease due to the reduction of alkalinity
and the increase of dissolved carbon dioxide. This study evaluated the effects of calcium hydroxide, sodium
carbonate and bicarbonate in maintaining water quality during the cultivation of L. vannamei in BFT. The ex-
periment was conducted using juveniles stocked in 150-L 12 tanks at a density of 333 shrimp/m3
four treatments with three replicates each: T1 — Na2CO3, T2 — Ca(OH)2, T3 — NaHCO3 and T4 — control. For
pH correction, alkalinity and both pH and alkalinity corrections, we used sodium carbonate (0.06 g/L), sodi-
um bicarbonate (0.20 g/L) and hydrated lime (0.15 g/L), respectively. Significant physical, chemical and bio-
logical differences (Pb0.05) were detected among treatments. Control shrimps showed lower growth
performance (Pb0.05) than shrimps in other treatments. Hydrated lime and sodium bicarbonate appeared
effective in supplementing alkalinity, whereas the soda ash did not. We verified the effectiveness of sodium
carbonate in raising pH levels and assisting in supplementing alkalinity. This study demonstrates that the re-
sults obtained in the control treatment levels of alkalinity and pH decrease during rearing, and that CO2 levels
would be increased in super-intensive systems with bioflocs without water renewal.