The Monitors & Controllers can function as a digital light timer, digital temperature controller, pH controller, and aquarium monitoring system. For example, a pH probe connected to the controller becomes a monitor and controller, measuring pH and releasing alkalinity/buffer to maintain steady pH.

The Neptune Apex controller is the premier Monitors & Controllers, with numerous available modules including an aquarium doser. An automatic fish feeder. Neptune Systems has high-end modules and components for the most demanding aquarium.

The GHL controller is a top-notch aquarium dosing system that incorporates an advanced aquarium monitor and equipment controller. Most aquarium controllers require the purchase of a base system to control the various modules.