The FMK Flow Monitoring Kit by Neptune Systems is an essential tool for saltwater and freshwater aquarium enthusiasts looking to gain precise control over their systems. This kit includes a Fluid Monitoring Module (FMM) that connects to any Apex model via the AquaBus port, offering multiple monitoring functions such as flow rate measurement, leak detection, water level sensing, and more. The package comes with various sensors and adapters designed for different applications, including two FS-100 flow sensors for larger pipes and two FS-50 flow sensors for smaller tubing, along with unions and adapters to fit a variety of plumbing setups.