We recommend only using distilled water in your Opal to help reduce the potential for mineral buildup. It is recommended that you follow the instructions in the owner’s manual for your unit regarding the schedule of running descaling and sanitizing cycles. Using vinegar in the descaling cycle can help break up the minerals as well. It’s important to note that distilled water is different from bottled water, reverse osmosis water, filtered water, or spring water. All of these other options contain varying levels of minerals that can build up in the unit and impede optimal operation. Using distilled water reduces the frequency of descaling and cleaning. Using our scale-inhibiting filter, part P4INKSFLTR, is designed to increase the time between cleanings and reduces the solidification of scale. It is recommended that there be at least 4” of clearance in the back, on both sides, and above the Opal to allow proper air flow so that the fan can move air about the unit.