How to measure KH automatically: Kh keeper Plus Review

by | Nov 30, 2022 | Reef | 2 comments

We finally have in our hands the new KH keeper Plus by Reef Factory, the continuous KH monitoring system for marine aquariums, that we tested thoroughly.

KH keeper is a KH meter, extremely compact, that doesn’t require any other device to work. Reef Factory says that it has an accuracy of 0.01 dkH. We actually don’t require it to be THAT precise, but we do really like this very high resolution.

For us mere mortals who go crazy to read a tritrimetric test, not knowing if there’s a color change… it’s a great step forward.

You can schedule anywhere between one and 12 readings per day. The nice thing is that the value of a reading is too different from the previous one, KH keeper immediately does another test to be sure of the reading, which keeps us us from being alarmed by a false reading.

We set it for two readings per day, one at midday and the other at midnight. We wanted to see if there was a difference between night and day, but there wasn’t.

How to measure KH automatically with KH keeper Plus by Reef Factory: unboxing, calibrations, set, and comments in our video


The device

KH keeper Plus is a really compact device, that houses three dosing pumps, a beaker and a pH probe. Moreover, it also includes a client WiFi that needs an Internet connection to work.

In the package there are also two calibration solutions for pH 4 and pH 7, the liquid for the measurements, and a precision scale for the calibration of the system. The first thing to do once you take the device out of its packaging is assemble it and plug it in. Now you can link to the WiFi address provided by the device and through the browser, go to Then you only have to fill fields and calibrate it.

The calibration of the KH keeper Plus

We can’t deny it: the calibration is long and boring, and you have to repeat it at least once a month.

As you can see from the screen of the app, you have to complete three tasks. First you have to calibrate the pH probe with the two solutions at pH 4 and pH 7. Then you have to test the accuracy of the dosing heads. There are three heads in total, but we want to test the one that fills the beaker and that one that doses 5 ml of reagent in the beaker.

Once this calibration is done you’ll have the beaker with the reagent that you diluted with osmosis water. I used two bottles of still water, but you can use something less voluminous. You have to find another container for the drain. In this case, I used a two-liter bottle. But if you have a drain nearby you can flush everything directly. The two-liter bottle lasts about 10-15 days with two measurements per day; you can find your own balance, and remember to empty it once in a while.

The device has two buttonholes on the back to fasten it to the cabinet of the aquarium. For this review, we put it on the osmosis tank, but at some point, we’re going to fasten it to the back of the cabinet.

KH keeper Plus has a series of LED lights inside, very pretty. We set it so that if the KH reading is between a range of values we chose, the device lights up green, and if it isn’t inside the range it lights up red. While the device is making the measurement, it lights up blue, as you can see in the following pictures.

KH keeper is controlled by an app on your smartphone, or through the Reef Factory‘s website. Once it takes a measurement, you can see the values in the app or you can be warned by notifications. Very convenient and efficient.

Finally, you can see the graph with the KH trend through time.

Above is the KH trend since I first inserted KH keeper Plus in my system. Where you see the values getting higher it is when I dosed a buffer to raise my KH level, which was too low.

KH keeper Plus: contents of the package

We still haven’t done an ICP to compare the values measured by KH keeper Plus. But knowing our aquarium and having ELOS kit tests we can say that the accuracy of these two methods are the same.

Dosing pump

And the costs of KH keeper Plus?

KH keeper Plus is sold at 795 euro ($825 USD). As you have read, KH keeper Plus can do up until 12 readings per day. If you want to dose your aquarium automatically, you have to purchase the KH keeper Pro, or use the keeper Plus with the Dosing Pump from Reef Factory. We still have the dosing pumps, we only have to set them and then we will report to you about how the complete system works.

The reagent is sold in packages of 1 and 2,5 liters. For a measurement you need roughly 5 to 15 ml depending on the KH value of the aquarium. So, with one liter you can do about 1250 tests, which means that if you do one test per day it would last 4 years!

The system works with a KH between 5 and 15, and I think that using more would be a waste.


What can we add? We really loved KH keeper Plus. During this first month of testing, it proved itself to be accurate, and it always warned us via email, smartphone and on the watch when the KH was over the range we set. At first it was between 7 and 8.

It sure simplifies the managing of our reef aquarium, because based on the daily value we can adjust the calcium reactor, the balling system, or the dosing of other products without the fear of going too far. Or, even better, we can automatically manage the balling system and/or the calcium reactor.

Moreover, being able to read the KH is particularly important when we’re not at home, like if we’re on holiday or at work.

Well, it has a price. And not so low. 795 euro isn’t a joke. But in an aquarium of hard corals it isn’t that much, especially when it brings many simplifications to our system, not to mention the safety. And the ones that benefit the most are our corals.

If you have any questions or thoughts let’s talk in the comments in our forum or on other social channels like instagram.


The functioning is always flawless (at least during our month and a half of use);
Compact and easy to set;
Extremely precise;


High price.

KH keeper Plus – final summary

Construction quality
Quality price ratio


Disclaimer: the KH keeper Plus device we tested has been provided directly from the official Italian distributor.
[Translated by Agnese Poggi]

  • danireef

    Danilo Ronchi, aka DaniReef lives in Italy where he is hydraulic engineer, but starting from his love for reef aquarium and photography, he began to write about marine aquariums from 2006 and now he's published his first book "Marine Aquarium". From 2007 Danilo writes on his blog where publishes articles, pictures, product reviews, aquariums coverage, reportage and history of his tank. Now he's happy to be part of


  1. Krzysztof

    Unfortunately after one tear of use my experience is not that great as your review. There are constant problems with PH probe used by company, need constant re-calibration, quality of reagent pump is also far from ideal, needs monthly rechecking. After sales service is slow and hard to get any proper response from them. So , as described idea of product is brilliant, implementation not that great.

    • danireef

      Thanks for your feedback. I’m using for far less months than you, but I’ll check in the near future. Thanks again.


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