Due to potential mercury contamination and UV exposure, the MVI mercury vapour indicator should only be opened by Ion Science Ltd authorised service centre, trained to service the MVI. External carbon filters and water trap filters should be replaced after 120 hours use, or as required, to minimise the risk of contamination of internal components. When a filter is showing signs of contamination replace immediately. Please refer to the maintenance section of the MVI user manual for further guidance on MVI health checks that can be carried out.