A disinfectant composition useful in shrimp aquaculture and a process for using such a disinfectant, in which there is a composition containing a) 25 to 87 wt. % of KHSO5 containing triple salt b) 1 to 20 wt. % of at least one H2N(CH2)nSO3H compound with n being 0, 1, 2 or 3, c) 1 to 8 wt. % of a surfactant d) 1 to 60 wt. % of a C2-C10 aliphatic dicarboxylic acid, optionally substituted with a hydroxyl and/or carboxylic group and e) 10 to 30 wt. % alkali metal phosphate.