GHL KH Director Overview

Overview of the GHL KH Director

The KH Director is one of the latest, and possibly greatest, products from GHL. It is a specialized aquarium automation device designed to analyze the alkalinity of your aquarium water, then report the current dKH value, and if configured, make any adjustments to dosing levels. The unit requires a set of three dosing pumps to perform the analysis, and an optional fourth pump to take corrective actions to keep your dKH level stable. Due to this requirement of dosing pumps, most customers will purchase the KH Director as a combo set which includes either a stand-alone doser 2.1, or a slave doser which is used with the GHL ProfiLux controller system. I personally utilize the ProfiLux 4 on my aquarium, so I will be discussing and reviewing the slave combo set.

What’s included

KH Director / Doser 2.1 set includes the following:

  • KH Director device w/ integrated measuring cell
  • Specially designed pH electrode for KH measurment
  • Calibration fluid
  • 500ml reagent bottle
  • Silicone hose
  • Power supply splitter cable
  • PAB-cable (50 cm / 19.6? length)
  • GHL Doser 2.1, 4 pumps (Stand Alone or Slave)
  • 24V Power supply
  • 8x Plastic tubing adapters
  • 6ft USB cable

Both KH Director Combos can be purchased here:

Stand Alone Combo

Slave Combo

KH Director Operation

The Video below shows the entire analysis process in high speed, the actual process takes anywhere from 10 – 20 minutes to complete. When the analysis of the water sample is complete, the KH Director flushes out the used sample and also will record the data for reporting purposes as well as make adjustments to your alkalinity dosing if you choose to configure it.

In the first step of the operation, the KH Director vents the internal reagent tube, it then flushes and de-aerates the tubes to prevent any air bubbles from entering the sample which could potentially cause inaccurate results. Once this is complete the first pump activates to draw a sample of water from your sump to use for the analysis. The amount to be drawn is configurable in the GHL Control Center App and can be set from 50-100 ml, with a default of 80 ml.

The next part of the process is the analysis segment, the second pump activates and draws in the correct amount of reagent required based on your configured sample water volume. So if you choose a sample volume of 50 ml, the KG Director will use less reagent than it would had you chose a 100 ml sample. This will allow you to extend the life of your reagent supply, however you will get more accurate results when using a higher sample volume.

Once the sample analysis is complete, the third pump turns on to drain all water and reagent in the KH Director to a waste container, and prepares the unit for the next cycle.The dKH measurement is shown in the GHL Control Center application and recorded for charting  and reporting.

If you choose to utilize the fourth pump, you can assign it in the GHL Control Center application so the KH Director can modify the dosing amounts as needed based on the testing results. To achieve the most consistent Alkalinity, it is recommended to allow the KH Director to alter and control your alkalinity dosing. This way, if the water analysis results in a dKH reading higher than your configured desired value, the dosing volume will be decreased, and if the dKH reading is lower than desired, then the dosing volume will be increased. I am currently not utilizing this automatic adjustment option since my KH Director is still new and I want to give it some additional time for a ‘Break in’ period. Although this is not required, it just gives me more confidence in my own configuration.

Watch the video below to see the actual operation and control of the pumps, I have also included a screenshot of my KH Director settings from the GHL Control Center as well as the comparable dKH reading from my Hanna Instruments checker.


KH Director Testing Process


GHL Control Center KH Director
dKH reading in GHL Control Center
dKH reading from Hanna Instruments alkalinity checker
dKH reading from Hanna Instruments alkalinity checker

Buy your KH Director combo or other GHL automation equipment here

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