Housing Sump O-Rings: The GE Merlin 1240326 Housing Sump O-Rings should be replaced every couple of filter changes or when there is damage to the o-ring. Use o-ring lubricant to keep the oring effective at sealing the housing sumps.
Change your filters and membrane at the recommended frequency, and clean your system with a product like Sani-System SS96RO, an easy to use, pre-measured, reverse osmosis system sanitizer, available below.