Evolution Aqua Nexus Auto Cleaning SystemsEvolution Aqua Nexus Automatic Cleaning System Fully Automated Cleaning Cleaner Water, Less Effort The Nexus Automatic Cleaning System takes the hassle out of maintaining your Evolution Aqua Nexus 220 or 320 filters by automating the entire cleaning cycle. Whether your system is gravity fed or pump fed, this smart upgrade means no more manually switching pumps, opening valves, or handling dirty filter media. Just set it and forget ityour filter stays