Pure, clean water is a priority for almost all animals, plants, but also fish. No aquarium equipment is more efficient in creating ideal conditions of water for integration in aquarium than a reverse osmosis unit.
Reverse Osmosis water is substantially free of chlorine, nitrates, phosphates and heavy metals and is an ideal basis for saltwater or freshwater aquariums or the replacement of evaporated water.
Tap water is generally full of these pollutants, and the effect on your aquarium may be severe enough depending on how bad the water is in your area, fueling and enhancing the growth of algae and diatoms that must then be treated with Chemical methods. Because reverse osmosis filters remove all these dirt, they are becoming more popular amongst aquarium hobbyists.
Depending on the quality of your tap water, it may be more costly to deal with the effects of higher levels of TDS (the level of inorganic and organic compounds) in your aquarium water compared to buying a reverse osmosis unit.