Out of Stock Neptune Systems Fluid Monitoring Module (Module Only) - Neptune Systems $104.95 FMM – FLUID MONITORING MODULE IT DOES SO MUCH! This is just the module itself without and sensors. The FMM (Fluid Monitoring Module) is a module that connects to any Apex (Apex(2016), Apex Classic, Apex Lite, Apex Jr.) via it’s AquaBus... Out of stock