RO/DI (Reverse Osmosis/Deionization) filters will assist in the removal of impurities from your tap water such as chloramine, heavy metals, chlorine, and phosphates. These impurities can contribute to the growth of algae and in some cases cause an even larger issue if not treated properly. The tap water will filter through the sediment cartridge first and then through a carbon based block filter. The two filters combined will remove the sediments, pesticides, and chlorine. After that, it will then travel within the RO housing membrane to be further filtered. The membrane usually removes over 96% of nitrates and up to 99% of silicate from the water source. For standard RO filters, this is the last step in the process. However, with RODI units the water will then run through a DI resin cartridge for further purification purposes.