Summary #

The GHL Doser is a high-precision, automated liquid dispensing system designed for aquarium maintenance. This article provides an overview of the Doser models (Standard and Maxi), the underlying technology, and the modular Standalone (SA) and Extension (EXT) architecture.

Applies to #

• GHL Doser 2 / 2.1 / 2.2 (Maxi)
• GHL Doser 3 (Maxi)

Overview #

Automating fluid management is a key factor in maintaining a stable reef or freshwater environment. GHL Dosers utilize high-quality stepper motors to move liquids with extreme accuracy. Whether you need to add tiny amounts of trace elements or move large volumes for water changes, the Doser lineup is designed for every scale.

To cover different applications, the Doser is available in two primary hardware variants:

• Standard Doser (up to 4 pumps): Optimized for maximum precision. It is the perfect choice for daily supplement dosing, such as Balling methods, Triton, or liquid coral foods.
• Doser Maxi (2 pumps): Built for heavy-duty tasks and higher flow rates. With its more powerful motors, it is ideal for Automatic Water Changes (AWC) or continuously feeding calcium reactors.

How it works #

1. Precision and Reliability #

The GHL Doser is engineered for exceptional dosing accuracy. By using high-torque stepper motors, every rotation is precisely controlled by the software. This allows the system to maintain a consistent flow rate and reliably monitor container fill levels, ensuring that your aquarium receives exactly what it needs without manual intervention.

2. Modular Architecture: Standalone (SA) vs. Extension (EXT) #

The system is fully modular and can grow with your hobby, supporting up to 32 individual pumps. The setup distinguishes between two operating modes:

• Standalone (SA): This unit serves as the “Brain” of your dosing station. An SA Doser features its own integrated controller and Wi-Fi, allowing it to connect directly to the GHL Connect App or myGHL Cloud. It stores all schedules locally and can act as a Master device to control additional units.
• Extension (EXT): An EXT Doser acts as a cost-effective expansion without its own internal controller or Wi-Fi. It must be connected to a Master device (ProfiLux or Doser Standalone) via a PAB (ProfiLux Aquatic Bus) cable to receive its commands.

System Requirements #

• For Standalone operation: A mobile device or PC for configuration via the GHL Connect App or GHL Control Center. Connection can be established via Wi-Fi, USB, or LAN.
• For Extension (PAB) devices: A Master device is required — either a ProfiLux Controller or a Doser Standalone — along with a PAB cable to establish the data connection.

Examples / Use cases #

Use Case 1: Precise Supplementation (Standard Doser) #

A user wants to maintain stable Alkalinity and Calcium levels. They use a Standard Standalone Doser and program the dosing tasks to be spread across many small increments throughout the day. The app automatically tracks the remaining liquid and sends a notification when a container needs refilling.

Use Case 2: Automatic Water Changes (Doser Maxi) #

To maintain water quality without manual labor, a Doser Maxi EXT is connected to an existing ProfiLux. One pump removes old tank water while the second pump simultaneously adds the exact same amount of fresh saltwater. The robust Maxi motors handle these larger volumes with ease.

Use Case 3: System Expansion #

A user who already owns a Doser for core supplements decides to start dosing additional trace elements. Instead of purchasing a second Standalone unit, they add a more affordable Doser EXT. Connected via PAB, the new pumps can be configured as “Pumps 5–8” in the existing app interface and are managed centrally.