ProtoxHysan is a disinfectant - that is, it kills the mould and cleans the surface. However, as ProtoxHysan leaves no residue of the active ingredient, it has no preventive effect.
If there is a risk of mould recurrence, you should carry out a preventive treatment with ProtoxProtect after cleaning with ProtoxHysan. In addition, the source of moisture should be identified and removed before combating the mould infestation.