KHG Monitor: Assembly, Installation & Operation

If there is a single test that aquarists can run to give them a reliable reading on the overall health of our aquariums, it is Alkalinity.  If our tank’s Alkalinity is good, there is a very good chance that every other element in our tank is also doing well.  Alkalinity is usually one of the first things to swing when things are starting to go wrong. 

Dr Bridge, the creator of the KHG Controller has now released its KH Monitor. 

Like it’s bigger brother the KH Monitor can automatically test your tank’s Alkalinity without any involvement from the aquarist.  No more filling a vial, swirling for 30 seconds, counting drops or pushing buttons.  The KH Monitor is a reliable and accurate way to assess the health of your aquarium.

Also with the release of the KH Monitor, Dr. Bridge has also released its long anticipated Advanced Interface Module also referred to as the AIM.  This little box allows you to connect your KH Controller or Monitor to any 3rd party system controller such as the Reef Angel or Neptune System’s APEX. 

All you need is a free pH input port on your 3rd party controller to connect and transfer the readings from the KH Monitor to your controller’s cloud interface! 

In this article, we will cover the setup and installation of the KH Monitor.  If you are looking for instructions on how to install your Advanced Interface Module to your controller or monitor, please watch our “KHG: Advanced Interface Module” video.

The box should include:

  • KH Monitor Unit
  • Power adapter
  • pH Probe
  • 500 micron filter Check valves
  • LCD connection cable
  • Concentrated reagent solution
  • pH Calibrating Solution

Before we start the installation, there are a few things that we need to have available. 

  • Ethernet cable to connect the KH Monitor to your home router
  • 1500ml of RODI water to create reagent solution
  • A level

Creating Reagent Solution

The KH Monitor comes with a pocket of concentrated reagent that must be diluted at the right concentration to ensure accuracy of testing.  All you need to do is take 1500ml of RODI water (or for increased accuracy, you can weight 1500 grams of RODI) and mix in the reagent.

The newly created solution does not need to be refrigerated and the reagent will usually last around 45-60 days if testing once every 4 hrs. 


Assembling and Installing the KH Monitor

Assembling the unit is fairly straight forward and simple.  The dosing pumps are already set up and the lines have already been installed. 

When assessing the optimal location for the KH Monitor you need to keep in mind the following important criteria:

  1. The KH Guardian should be installed within 3 feet of your water source. This means that the intake line that pulls water from your tank to the unit must not be more than 3 feet long. 
  2. The KH Guardian must be placed in a flat and level surface.
  3. The KH Guardian must have access to Ethernet cable and connected to your home network. While a connection is not required for day-to-day operation, a connection is required to configure the unit and access historical data. 
  4. The KH Guardian is not water proof.

To assemble the unit, start by connecting the LCD display to the KH Monitor main body using the provided white connection cable.  Connect the cable to the bottom of the LCD monitor and then connect the other end to the TOP Ethernet jack on the side of the KH Monitor.

Install the included 500 micro filter check valves to both the SW IN (Salt Water In) and Salt Water Out (SW OUT) lines.  Be sure to install the check valves in the correct direction. 


Now, place the KH Monitor on a flat surface.  Place the SW IN line in your tank and secure it in place.  Be sure to avoid any kinks and that the end of the line is clear all around.  You don’t want the end of the line touching the bottom of the sump where it can pull in detritus and throw off the results.

Next, go ahead and setup the SW OUT line.  This is the line that will discard of the old testing solution.  The reagent is 100% safe so it can be safely returned back to your tank.  Now we understand that some people may not feel comfortable so you can also connect the line to a waste collector for later removal.  At the end of the day, it is your choice.

Now, connect the reagent solution line, labeled KS, to your reagent solution bottle.

We are almost there. Connect the KH Monitor unit to your home router by using an Ethernet cable and connecting it to the bottom jack on the side of the unit.    Make sure that your home network is running DHCP.  If you aren’t sure about your network setup, please refer to your router’s user guide. 

Last, connect the power supply to the side of the KH Monitor and then to your electrical outlet.  Be sure to install the power supply using proper drip loops to prevent the unit from getting wet.

Calibrating and Installing the pH Probe

Take the pH probe included with the unit and remove the small storing container attached to it.  Once the pH sensor is exposed, rinse it with RO water and then pat dry with a towel.  Do not twist dry the probe as it may damage the sensor and render the probe inaccurate.

Place the probe into the pH 7 calibration solution and ensure that the sensor is fully submerged.  Press and hold LCD buttons 2 and 4 simultaneously for 3 seconds until you hear a beep.  Release the buttons to complete the high calibration step. 

Now, before proceeding to low calibration, rinse the probe with RO water and pat dry with towel.  As before, do not twist and dry the sensor. 

Insert the probe into the pH 4 calibration solution making sure that the sensor is fully submerged.  Press and hold LCD buttons 1 and 4 for 3 seconds.  Once you hear a beep, release both buttons and allow for the calibration to complete. 

You must perform the 2-point calibration in order to use the KH Monitor.  You will not be able to proceed to the next step until calibration is completed.

Now, go ahead and insert the pH probe into the KH Monitor probe holder.  Line up the bottom edge of the pH probe rubber handle to 1 mm above the bottom edge of the titanium block on the KH Monitor unit.  Tighten the thumb screw to hold the probe in place.  DO NOT overtighten the thumb screw as it may break the probe. Complete the process by connecting the probe to the back of the KH Monitor.

Connecting to Your KH Monitor Web Interface

After switching on the KHG, the display panel will show the IP and port number automatically assigned by the network DHCP – Do not worry if you miss this initially – it will display in a cycle after fully booted.

Please write down the IP and port number shown on the display and enter it on your computer or mobile device browser page. 

If the connection to the KH Monitor is successful, you will see a simple login page appear.  Go ahead and type the password “Admin” with upper case A to login. 

In this video we are going to cover basic configuration to get your unit working as soon as possible.  For a more in depth description of each section, please refer to the User Guide which can be downloaded directly from

Once you have accessed the main control page, click on “System Setup.”

Under the system setup, find “Check Interval”.  This field allows you to tell the unit how often it should run an alkalinity test.  The unit can test as often as 30 minutes and up to once every four hours.  Since changes in our tanks usually happen slowly, we recommend that you set the Check Interval to 240 minutes or once every 4 hours.  This will allow any changes to fully take effect before testing and possibly adjusting again.

Make sure that “Enable KH Auto” is activated by entering a value of 1.


We are almost ready to start using our KH Monitor.  Once the unit has restarted, check the IP address assigned to it and enter that into a browser window to access the web interface.  Login using the password “Admin” with upper case A. 

Before we can start using the unit, we need to purge air from the lines.  First, click on the “SW Tube De-Gas” button.  This will make the unit pull water from the tank into the testing chamber.  You may have to do this several times until the LCD no longer shows S.W_ERR. 

Next,  prime the calibration fluid line.  To do this, click on “KS De-Gas” button.  As the machine primes the line, look into the observation window and check if the KH reagent solutions is dropping into the reactor chamber.  Once you see drops begin to fall into the reaction chamber, press the “RESET” button to stop.


Finally, go ahead and click on the “RESET” button.  At this time, all error warnings will be removed from your web page and the LCD on the unit should display STANDBY followed by a number which is the number of minutes until the next text. 

Testing the KH Monitor

Now we are ready to test the unit and get our first KH reading.  As with any equipment, it needs to break in so we recommend to manually run 5 tests first to ensure optimal performance and accuracy.  To do this, just click “Get dKH” on your unit’s main web interface screen.  The unit will beep and begin the testing process.  It may take up to 7 minutes for the unit to run a single test.  Once the test is completely manually repeat the process to ensure that the unit breaks in correctly.   It is normal for the unit to reboot after each test. 

Reading the KH Monitor

Reading the results of the KH Monitor is super simple.  The easiest way to do so is to read the LCD screen.  You can find the value of the last test on the lower right hand corner.  On the left corner you will see the pH value of your salt water at the time of testing. 

You can also access this information by connecting to your KH Monitor via it’s web interface. At the bottom of the main screen look for “Last KH.” 

If you want more detailed information about this section including an explanation of what the other data displayed means, please refer to the KHG User Manual which can be downloaded from our website at

Accessing Historical Data

To access a table of running historical data, head over to your KH Monitor web interface and click on “Display Record”.  This area will show you every single test result along with other pertinent data such as the time it took to draw water from the tank.  This information is handy in assessing the life of the 500 micro Check Valves.  As the number gets higher, it means that it is taking longer for the unit to draw in water which could be caused by a clogged check valve.

Calibrating your KH Monitor

Sometimes you will notice that while the KH Monitor is very precise, meaning it is giving you consistent readings, it may not be accurate as compared to other test kits.  If this is the case, you can make adjustments to the readings to reduce the deviation between the two different testing methods. To make this adjustment, access the KH Monitor's web interface and click on the “System Setup” button.  Now look for “ADJ KH” and enter the difference in KH value.  For example: If the KH Monitor is reading 8.9 dKH but other test kits are telling you that the alkalinity is 8.5, you would enter -.4 as the value. 

Frequently Asked Questions

 How often should I calibrate and replace the pH probe?

 We recommend you calibrate the probe once every 4 to 6 months and replace it once every 12 to 18 months. 

Can my KH Monitor make adjustments to my Alkalinity?

No, the KH monitor is only that, a monitor.  It can be paired with a 3rd party controller so that the monitor can test you dKH and then the controller can react to the reading provided.  Also, Dr Bridge also has the KHG Controller which is an all-in-one solution that tests and controls your Alkalinity.

My KH Monitor is showing a pH reading that is lower than my tank's reading.  What is wrong with it?

The KH monitor does not test your tank’s pH.  The pH probe is there to test the solution as reagent is being added to it.  The KH Monitor uses the changing pH level of the testing solution to know when the test is complete.  The KH Monitor is displaying the pH of the testing solution and not the pH of the water in your tank.




Author: Carlos

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