Fauna Marin is the darling of the complex chemistry ULNS tank world.  Already offering unique “balling” formulas and purpose built dosers, they recently updated their all-in-one Zeovit reactor, the Technic Zeomatic, which includes a novel self cleaning feature to keep your media clean.  The system is designed for use with Sicce pumps and does not require an external air pump, which eliminates some extra equipment in your setup.  The new model also supports external use, meaning you don’t have to put it directly in your sump, so it is effectively much more like a calcium reactor in design than other reactors that are prone to leaks or water escaping the system.