Reef Factory KH keeper Plus

Achieving ideal conditions in a saltwater aquarium is crucial for the health and development of its inhabitants, especially corals. A key parameter that requires constant control is carbonate hardness (Kh).
Maintaining the appropriate level of Kh is important not only for the proper development of coral skeletons but also for their vibrant coloration. In the case of a marine aquarium, especially with stony corals, maintaining a stable level of Kh is essential. Fluctuations in Kh can stress the corals, negatively affecting their condition, growth, and coloration.

To maintain a consistent level of Kh, regular monitoring of this parameter is necessary, along with dosing the appropriate supplement to keep its level proper in the tank. There are various methods for measuring Kh, from manual droplet tests, which can be time-consuming, to automated solutions.

One example of a device for automated testing is the Kh Keeper Plus from Reef Factory. This advanced device automates the process of measuring Kh, providing users with precision and reliability in the Smart version, significantly easing the maintenance of optimal conditions in the marine aquarium.

Reef Factory KH keeper Plus Diagram

How the Kh Keeper Plus Works

The Kh keeper Plus is an automated device for monitoring the Kh value in a saltwater aquarium. This device takes a water sample directly from the aquarium and conducts a Kh measurement in a special reaction baker. After the analysis is complete, the Kh keeper Plus sends the results to the Smart Reef app. The aquarist has the option to decide what happens to the water after the test is finished. It can either be discarded into the drain or returned to the aquarium.
Moreover, the Kh keeper Plus allows for integration with a liquid dosing system. Through the Smart Reef app, users can connect the Kh keeper Plus with dosing pumps and automatically adjust the dosing based on current Kh measurements. This solution enables precise maintenance of the aquarium water parameters within optimal ranges

Product Features

  • Automated KH measurement in saltwater aquariums
  • Measurement accuracy up to 0.01 dKH
  • Measurement cycles ranging from 1 to 24 times per day
  • Smart Reef mobile app for Android and iOS
  • Stores measurement history for up to 1 year
  • Automatically signals abnormal Kh values in the aquarium
  • Supports automation of parameter maintenance (compatible with dosing pumps)
  • Quiet operation and compact size: The device operates quietly and does not take up much space.
  • LED backlighting: During measurement, the device glows blue. Green indicates a proper KH level, while red signals a deficiency or excess.
  • Starter reagent included in the kit (concentrate)
  • Smart Features
  • Management from a phone using the Smart Reef app, with Wi-Fi connectivity.
  • Setting the frequency of automatic measurements.
  • Measurement history available for up to a year.
  • Notifications for Kh deviations beyond the designated range, alarm for rapid Kh changes.
  • Ability to conduct tests outside the scheduled times.
  • Information on reagent consumption and the need for device calibration.

Kh, the Most Important Parameter in Saltwater Aquariums 

Alkalinity allows us to determine if our corals are doing well. An increase in Kh consumption indicates that the metabolism of the corals is increasing, which means they are growing faster. If the Kh level rises, it can stress the corals. In such a case, we need to identify what is causing the stress and resolve the issue.

Reef Factory KH keeper App

Stabilizing Parameters in a Saltwater Aquarium (Actions in Smart Reef) 

Stability of parameters in a saltwater aquarium is crucial. One of the important areas is water chemistry, where the Kh keeper Plus device plays a significant role. In a saltwater aquarium, it is often assumed that all elements are consumed evenly. This means that a change in Kh level suggests parallel changes in other parameters, such as calcium (Ca), magnesium (Mg), potassium (K), strontium (Sr), iodine (I), boron (B), and others.

An increase in Kh consumption is usually associated with increased consumption of these other elements. In the Smart Reef app, in the 'Actions' section, there is the option to integrate Kh Keeper Plus with a dosing pump system. As a result, if the aquarium uses components consisting of three bottles, Kh keeper Plus can be connected with three dosing pumps. We then set a dependency where a change in the Kh level in the aquarium (increase or decrease) causes the Smart Reef app to automatically adjust the next dose on the dosing pumps.

This is a mechanism for dosing components aimed at maintaining a stable chemical state of the water. Based on the Kh measurements, we influence the value of the next dose on the dosing pumps, which allows for the automation of the process of maintaining the appropriate chemical parameters in the aquarium.

Reef Factory KH Keeper

Alarms for Deviations or Rapid Changes in Kh 

If Kh levels go beyond the set safe range, you will receive a push notification on your phone, watch, or other mobile device.


Reef Factory KH Keeper

Measurement History

You have access to the history of Kh measurements, going back up to 1 year


Reef Factory KH Keeper

External Light Indicators of the Device

Blue color indicates that the measurement is in progress. Green color signifies that the Kh measurement is within the normal range. Red color indicates that the measurement is outside the safe range.


Reef Factory KH Keeper


There are concentrated versions of the reagent available to the user, which are mixed at a ratio of 1 serving of reagent per 9 servings of RO water. A 5L ready-made version of the reagent is also available. 

Shop KH Keeper Reagents


Technical Specifications

  • Dimensions: 5.35 x 3.82 x 8.27 inches.
  • Weight: 1340 g / 2.95 lbs.
  • Power supply: 100-240 V AC, 50/60 Hz.
  • Power consumption: 0.5-4.0 W.
  • CE certified.

Kit Contents: Device, probe, reaction vial, manual, calibration fluids, concentrated reagent, electronic scale, tubing, water filter holder, stirrer, power adapter, neodymium magnet. 
Smart Reef System

Reef Factory offers a wide range of Smart products, facilitating easy and convenient saltwater aquarium management. With the Smart Reef app, you can seamlessly integrate various devices into one system. Kh keeper Plus is part of the largest ecosystem of Reef Factory’s own Smart devices for marine aquariums in the world in our hobby.

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