Aquarium keepers are always looking to relieve their financial burdens, often moving toward more energy efficient lighting, selling off coral frags, or purchasing used equipment. One thing to not skimp on, however, is the quality of the water entering into your aquarium. Protein skimmers and water pumps may operate like new even years down the road. Tap water filtration units, specifically RO/DI units, do not fare too well long term. The physical structure of the filter holds up just fine, but they have many consumable parts that require routine replacement. Things like pre-filters, membranes, and DI resins all need to be replaced as they are used up, and not only is their replacement necessary to provide good quality water, but it’s also a little pricey. That said, having good quality water is the foundation of a pristine reef aquarium, and filling your tank with bad water will only cause issues that your aquarium filters won’t be able to handle forever.