Elos Water Test Kit Ca Calcium

Elos Water Test Kit Ca Calcium

After presenting, the last weeks, the Elos test kit alkalinity KH (here) and Magnesium (here), today I present the Elos water test kit Ca Calcium.

Iquitos - mangimi tropicali - Colombo

The Elos Test Kit Ca Calcium

As you can see from the photo, the test kit consists of a good-sized box that contains the folding paper with explanations, the leaflet, one glass tube with Elos symbol and its plastic cap, three small bottles containing the liquid reagent called A, C, D, a B powder reagent, a syringe and the classic Elos measuring spoon.

The resolution of the test is 10 ppm.

The reagent and the tube are contained inside a plastic bag.

Unfortunately, when they thought about the box, they did it slightly too low, so the “A” and “C” reagent bottles can’t stay standing but must be inserted horizontally.

Elos Water Test Kit Ca Calcium

The test is quite simple, but easy.

It fills the tube with 5 ml of aquarium water with the excellent syringe provided.

2014_03_elos_test_kit_001Then it needs to add 7 drops of reagent from the “A” bottle and 0,15 ml of powder from “B” reagent in the test vial.

We close the tube with the cap provided, being careful not to get hurt or not to break the tube, and shake gently for 30 seconds.

At this point we have to decide whether to use the high-resolution test, 10 ppm, or low-resolution, 50 ppm. I generally prefer an happy medium of the two we will see immediately after the description of the two methods.

The resolution depends on which reagent bottle is used for titration, the reagent C or D. C reagent resolution is 50 ppm, while the D reagent resolution 10 ppm.

elos misurino 0,4 0,15

Now, we have to add drops, from C or D bottle, until the color change has occurred towards blu from purple. It’s quite easy to recognize colour change when it happens.

At this point we have simply multiply the number of drops used until color change and multiply them by 10 or 50 depending on the reagent used.

For example, using 8 drops of reagent C would mean having a value equal to 8×50 = 400 ppm, while using 42 drops of reagent D would mean having 420 ppm of calcium in the aquarium.

Surely you already know which is the method that I prefer to use, which is also suggested by the Elos in the leaflet. Using the C reagent for the first 6-7 drops, or until reaching a value of at least 300-350 ppm of calcium, and then refine with the D reagent and obtaining in this way the resolution of 10 ppm, using the smallest possible number of drops.

Obviously the difference between the C and reagents is only in the dilution, they are the same identical reagents.

Even for the test of magnesium (here), such as KH (here) before it, the card does not show a reference color scale, since we are talking about a titration test and there are no predetermined values.

Elos Water Test Kit Ca Calcium leaflet

One of the things I like to mark is the dropper of the bottle, that is extremely accurate, and the drops are almost always identical to themselves. Elos claims to use a calibrated dropper, thing we can not verify, but, in any case, the result is great. Of course, sometime it might happen that a drop is filled by air and bangs, but my experience shows me a chance lesser than one drop for every box… I advise you to swirl the bottle before using the reagent.

Elos Water Test Kit Ca Calcium

In the back of the box you can read the reagents used, then also listed in the leaflet with instructions for use.

Elos fits the expiration date stamped with the date by which you should open the test, useful to understand if the test kit is good or not.

elos test carbonati kh

At the opening of this new test I noticed the color change was not in line with what happened with the others Elos water tests I used in the past, the combination of reagents A and B did not give me a fuchsia colored very strong as I used to. The thing, however, was not repeated in subsequent tests I did, and so after the first reading I have detected no significant difference between this test and the ones I’ve used in the past, similar colors as usual and absolutely comparable readings.

Do remember that all tests, although they have a high number of measurements, should be used not more than six months from their first use. Incorrect storage can ruin the reagents and give you false readings.

I recommend you always use your eye to evaluate the aquarium, do not rely only to test, and if the tests were to detect a value clearly wrong, before making any countermeasure would be desirable to do it again with other brands deemed reliable. Of course, an eye should check the expiration date, which is essential for such perishable reagents, especially if exposed to moisture and heat.

In addition to calibrated dropper, that for a titration test is absolutely critical, the mode of packaging and conservation are fundamental for right readings.

Finally you can download the instruction manual here: Elos water test kit Ca Calcium – manual


The test is not cheap since it costs 24,28 €, given my experience over time, I can also say results have always been in line with what is in the aquarium, given the many comparisons I’ve done with other tests. And the price is, in my opinion, the only limiting factor in this test.

For this reason, considering the read values aboslutely true, we believe this test absolutely recommended, but given the price a bit high value for money can not be higher than 4 and a half stars.

Build quality 4hstar
Value for money


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