Ultraviolet sterilizers are terrific pieces of equipment that bolster the filtration system of any marine aquarium, but they are typically met with mixed reactions and results. On the plus side, UV sterilizers are really effective at eliminating free-floating pests and algae, meaning they can significantly reduce the possibility of having a disease or parasite outbreak. On the negative side of the argument, the sterilizers can be expensive to buy and maintain, and they don’t treat all of the water in the aquarium. By that we mean they can only treat a small amount of the water at a time. An ozonizer, on the other hand, raises the ORP of all of the aquarium’s water at once, so it basically is treating the whole tank all of the time. Despite that, UV sterilizers are a staple for most large systems, especially those with a lot of fish.