KH Director

***Shown item is for KH Director ONLY

*** KH Director requires 3 dosing pumps to operate! If you do not have 3 unused pumps, we recommend purchasing a KHD/Doser 2.1 Set

*** The KH Director® is designed to work in conjunction with a GHL Doser 2 or GHL Doser 2.1 Standalone (NOT INCLUDED) or a ProfiLux® Aquarium Controller 4 or 3 with a Doser 2 (2.1) Slave (NOT INCLUDED) for operation. Please see configurationt tab for more options.

Monitor, Maintain, and Control Alkalinity with Ease

The upkeep of Alkalinity is the most important aspect of reef keeping. If you’re looking to achieve exceptional coral growth, Alkalinity testing is a must!

The KH Director is the result of more than 2 years of research and development into the automated Alkalinity monitoring and control department. As always, we’ve stuck to our fundamental belief in high quality and exceptional reliability to bring you a product that is built to last. Featuring a patent pending design, KHD utilizes lab grade quality test standards to provide precise results every time. KHD is built to provide aquarium hobbyists and professionals with a safe and reliable Alkalinity control product which presents great value, functionality, and practicality.


Automated Alkalinity Monitoring and Control

KH Director uses a modified pH probe to provide KH values. In terms of the KH test process, the 3 blue adapters on the KHD each connect to an available GHL Doser 2 or 2.1 dosing unit. One pump is used to feed tank water into the KHD. The second pump feeds the KHD with reagent fluid. The third pump extracts the test sample and used reagent fluid after a completed test, then dispenses it into a waste bin.

As tests occur, the 3 pumps automatically perform their assigned tasks and report the results onto a viewable data logging chart. This data is then viewable on myGHL, ProfiLux Touch, ProfiLux display, and additional external display unit.


Lab grade KH Measurement Accuracy

Measure your Alkalinity with lab-grade accuracy. With only a 100 ml water sample, KH Director® can provide measurement values with 0.1 ° dKH accuracy.


Extreme efficiency and cost-effectiveness

Here at GHL we understand the importance of on-going costs involved with automated KH monitoring and control. For the KH Director it was especially important to consider these costs and develop a highly-efficient, cost-effective product. A single 1000ml bottle of reagent can last for up to 3 months when testing is performed 4x per day at a KH value of 8.  The pH electrode used by the KH Director was specially designed for KH measurement and has an average lifespan of 1 – 2 years.


Seamless Integration with GHL System

Through the use of the PAB (ProfiLux Aquatic Bus) connection, KH Director® seamlessly integrates into the modular GHL aquarium system. The PAB connection ensures interference free communication with other GHL PAB-devices such as the GHL Doser 2.1 or the ProfiLux® 4.


Backwards Compatibility

We want you to grow with us! Even the ProfiLux 3 / 3.1 and GHL Doser 2.0 will be compatible with the KH Director.


Reagent Consumption

A single 1000ml bottle of reagent can last for up to 3 months when testing is performed 4x per day at a KH value of 8.



  • KH Director device with integrated measuring cell
  • Specially designed pH electrode for KH measurment
  • Calibration fluid
  • 500ml reagent bottle
  • Silicone tube 5 m
  • Flex-pvc tube 70 cm for reagent
  • Power supply splitter cable
  • PAB-cable (50 cm / 19.6″ length)

- Lab-grade KH measurement accuracy; KHD provides measurement values with 0.1 degree dKH accuracy
- Adjustable test sample volume
- Measurements per day adjustable
- KH value display via host device
- Higher accuracy and safety provided by additional valves
- Cost-effective and safe reagent fluid
- Automated Data-logging
- Automated liquid supply
- Kalk reactor control
- Low maintenance design
- Seamless integration w/ GHL system
- WLAN, WiFi, USB und cloud-service access via host device
- Alarm function
- Status LED for pumps
- Color coded LED-backlit GHL logo on housing cover shows system status at a glance
- Convenient to program via GHL free PC software or app, web, and cloud service
- Professional CAN Bus System ensures reliable and interference-free networking of all network devices.
- Ample accessories available!



Add-on Control Mode

Use between 1 and 5 dosing pumps to add liquids to the aquarium depending on the control difference, KHD automatically calculates the appropriate quantities. The dosages can be time-delayed if the liquids are not to be dosed at the same time and divided into several sub-quantities per day. It is also possible that the dosing pumps used follow a dosing schedule, the quantities calculated by the KHD are then added to this dosing schedule.


Adaptive Control Mode

In this mode, 1 to 5 dosing pumps can also be used to add liquids to the aquarium depending on the control difference. In this mode, you set a dosing schedule for the dosing pumps involved, and the quantities of the dosing plan are varied by the KHD. If the KH value is correct, the dosing schedule remains unchanged, if the KH value is too low, all quantities of the dosing plan are increased as a percentage. If the KH value is too high, the quantities are reduced. The quantity change is dependent on the control difference and is calculated automatically.


Calcium Reactor Control Mode

In this mode, a calcium reactor can be down-regulated depending on the KH value.
A calcium reactor is usually operated by CO2 addition and control of the pH value; the actual pH value in the calcium reactor is measured by a pH electrode. If you select this pH electrode in the KH Director Options, the KHD can switch off CO2 if necessary (KH target value reached), otherwise the normal CO2 control is activated. This mode is only possible with a ProfiLux aquarium computer.


KH Director® gives you the flexibility to run the device in one of two ways.

The KH Director® is connected to the GHL Doser 2.1 Standalone (or 2) via the ProfiLux Aquatic Bus (PAB-Cable).

GHL Doser 2.1+KH Director
With this option, the GHL Doser has full control over the measurement process and behavior of the KH Director. The GHL Doser will control both its dosing pumps and the valves in the KH Director. This will allow the doser to evaluate the measurement results and calculate the KH value.


The KH Director® is connected to the ProfiLux 3 (3.1, 4) and a GHL Doser 2.1 slave (or 2) via the ProfiLux Aquatic Bus (PAB-Cable).

ProfiLux+GHL 2.1 Slave Doser

With this option, the ProfiLux has full control over the measuring process and behavior of both the GHL Doser and KH Director. The ProfiLux will control the dosing pumps in the doser and the valves in the KH Director. This will allow the controller to evaluate the measurement results and calculate the KH value.