According to werner theory primary, secondary of central atom in  CrH2O6Cl3 Complex respectively

3Cl- satisfies primary valency, 6 H2O satisfies secondary valency and the ligand satisfy primary and secondary valency is called duel valency, that means ligand involved in calculation of primary and secondary valency. Hence Cl- ligand act as primary and secondary valency in given complex CrH2O6Cl3.