A combination of methods may be beneficial where they are synergistic or where a level of redundancy is required.
It is essential to monitor the efficacy of water disinfection. This can be achieved by direct testing for pathogenic agents of concern, indirect monitoring of indicator organisms or monitoring of residual levels of disinfectants.
Management of chemical residues is important to avoid toxic effects on aquatic animals. For example, residuals formed between ozone and seawater such as bromide compounds are toxic to early life stages of aquatic animals and may be removed using charcoal filtration. Residual chlorine should be removed from water by chemical deactivation or off gassing.