Elos Potassium Test Kit Review


Elos recently released two test kits under their new “expert” test kit line. These are the Phosphate and Potassium test kits, of which we have reviewed the Potassium kit. Here we take an up-close look at it, and throw it up against a more popular potassium test kit, the KZ Kalium testkit. Potassium dosing is generally not recommended in most home reefs. It is usually dosed to help supplement dropping potassium levels in probiotic systems such as Zeovit or Ultralith. It is unclear if the potassium is absorbed by the zeolith or if the potassium is consumed by the beneficial bacterial to multiply. It is clear that shortly after starting Zeovit, potassium will drop significantly and this could cause problems. That is why it is paramount to check potassium if running Zeovit or something similair.

What’s in the box?

  • 2 – Standard Elos Test Vials
  • 4 – syringes
  • 1 – standard Elos measurement spoon
  • 1 – Test reagent powder
  • 1 – Aquatest RO water vial

Using the kit was pretty straight forward. Everything was easy to read and follow. The KZ Kalium test required you to move the test sample across a colored gradient scale until the color of the gradient is no longer visible through the sample. In comparison, the Elos test requires you to place a vial over a black dot on the test card. Then you slowly fill up the vial with the test solution, until the black dot is no longer visible though the test solution. Then simply fold up the test card and read the results.

The scale for the KZ test kit is considerably longer then that of the Elos test kit. Because of this, the KZ test can definitely give you a more precise reading. The Elos test kit is extremely easy to read, while the KZ takes quite a bit of practice to get used to it.

There are a few things I wished Elos did differently with this kit. There is really no need for a range of 100-600ppm, instead it should have been ranged from 200ppm-450ppm with markers every 10-20ppm. This would have been a lot more useful.


The Elos Potassium test kit was easy to use and very easy to read. Compared to the KZ test kit, the Elos wins hands down in that department. As I noted earlier, the actual precision of the reading could be a different story. One possible major flaw with the Elos test kit is the AquaDest Reagent. Elos only supplies 100mL of this reagent in the kit, only enough for 10 tests. While it could be possible to use our own RO water, packaging only enough RO water for 10 tests is rather ridiculous. KZ supplies enough K1 reagent for approximately 20-25 tests, bringing the cost per test to about $1.72 per test. The Elos test kit runs about $3.70 per test, possibly a lot less if we can use our own RO/DI water. Gauging the dry reagent, there should be enough for over 30 tests.

  • Easy to Follow
  • Clear Readable Results
  • Less Precise Reading
  • Not Enough Reagent

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