Salifert Calcium Test question

[returnofsid]

Hi Boomer,
I'm hoping you can "clear" up some confusion that I'm having, in respect to Salifert Test kits.

The calcium test kit has some wording that I'm unsure how to interpret. In the directions, it refers to the color changing from "pink-red to a clear blue color." The confusion is with the word "clear."

Does it mean a transparent blue color?
Does it mean an obvious blue color?

Here's why this is confusing. When testing, the color will change from a pink-red to a cloudy blue color. If I continue adding the CA-3 reagent, the cloudy blue will clear up, becoming transparent blue.

This would give me different "end points," resulting in differences in my calcium level.

For kicks, I just tested and here are my results.

Color changes to an obvious blue, but cloudy blue, resulting in a calcium level of 410.

Color changes to a "Clear," transparent blue, resulting in a calcium level of 425.

This has caused confusion for me, for a couple of years now, and I've usually split the difference. However, it'd be nice to know which interpretation is correct.

Thanks Boomer!!

 

[krisfal]

I know you are asking boomer, but I always interpreted to be at that point it becomes the transperant blue, else I would think they would just state "blue"

 

[returnofsid]

That would make sense. However, as it goes from pink-red to blue, it turns kind of purple, and then purplish-blue, then cloudy blue, then transparent blue...lol. I guess I've just wondered if "clear" blue means "obvious blue," just to mean not purplish-blue. I don't know. I just wanna get it figured out, so my testing will be more accurate.

 

[Krish]

I've always interpreted pretty much the same way as Kris did. Transparent, but with a blue tint to it.

 

[DonW]

Consistency is the key. I always just drip until my eyes see no purple. Im pretty sure everyone is going to see the color and color change a little differently. Comparing what my eyes saw to lab result the were close enough. I say dont sweat the small stuff.

Don

 

[returnofsid]

Except, from the point that the color obviously changes to blue, to the point where the color is a transparent blue, is a 15-20ppm difference, in my experiments. I admit that this 15-20 ppm difference isn't critical, but would like to be able to "know" my calcium, as close as possible, with the test kits, in order to most accurately balance Alk/Ca/Mg.

 

[DonW]

Except, from the point that the color obviously changes to blue, to the point where the color is a transparent blue, is a 15-20ppm difference, in my experiments. I admit that this 15-20 ppm difference isn't critical, but would like to be able to "know" my calcium, as close as possible, with the test kits, in order to most accurately balance Alk/Ca/Mg.

Unless you have some lab grade calibrated eyeballs the chances are pretty slim. You can however try for consistency and send a sample in for verification.

Don

 

[jake65]

Unless you have some lab grade calibrated eyeballs the chances are pretty slim. You can however try for consistency and send a sample in for verification.

Don

that would be nice...

 

[Slate]

This probably has no bearing on the color description we are talking about with the test kit. But the one thing I remember having drilled into my head during my chemistry labs was that the word "clear" references something being free of visible particulates. My teacher used to go crazy if we wrote that a solution was "clear" rather than colorless.

So, this could be referencing the cloudy appearance you get during the initial color change and waiting till it goes away? Basically I just felt the need to post something today....

 

[user 2204]

IMO I always go with the clear blue. I know what you're talking about with the cloudy blue/purplish blue. I just always go for the clear precise blue coloring. And like one mentioned, just be consistant.

Cheers,
Alex

 

[returnofsid]

Well, I just got a response, on another forum, from Habib. For those of you who don't know him, Habib is CEO of Salifert. This being the case, I'm going to trust his answer...lol.

I've also usually leaned towards the "transparent blue" being the end point, as I think most have. It would seem we've all been mistaken. Here's Habib's response.

Hi returnofsid

To make the clear blue more understandable....

The color change is from pink (say red) to blue. The change is gradual but within a span of something like 30 or so ppm.

When changing the pink/red portion will first partly become blue. Since blue and pink/red together give a purple color, that color is seen as an intermediate color. You will need 2 or 3 drops more to convert it to blue.

Blue is the color when the red/pink tinge, hence the purple color has disappeared.


Please keep in mind that once the purple color is seen you will need no more than 2 or 3 drops of Ca-3 reagent to obtain the blue color.

HTH

To which I responded, just to make sure I'm understanding his response, with:

Habib thank you so much for responding so quickly! Yes it helps immensely!!

So, to make sure I'm understanding what you're saying:

Cloudy Blue is the end point?

When I test, I do see the change to Purple. 2 or 3 more drops does change the color from Purple to a Cloudy Blue. 2 or 3 more drops changes the Cloudy Blue to a "Clear" or transparent Blue.

In the instructions, it specifies "clear blue." So my confusion has been with the definition of the word "clear," lol. It would seem that Salifert is defining "clear" as Obvious and not as Transparent.

 

[user 2204]

Thanks for the update and having an answer from Habib himself.

I am curious as to what Habib's answer will be in regards to the cloudy blue versus that of the transparent blue color change.

 

[returnofsid]

Continued responses.

I just googled for clear blue... it is a pregnancy test LOL!

Would an update in the instructions to "a blue without a red tinge" be more clearer?

LOL Yes, it is a pregnancy test!!

I do believe that a rewording of the test instructions would be helpful. I've actually posted this same question, on another forum. It seems most people read "clear blue" and understand it to mean "transparent blue." If this is the case, we're adding more re-agent than needed, to obtain the "transparent blue," which is giving us a higher test result than we actually have.


Maybe something indicating that the color will change from pink-red to purple and finally to blue. It's the word "clear" that I believe is throwing most people off.

 

[returnofsid]

Thanks for the update and having an answer from Habib himself.

I am curious as to what Habib's answer will be in regards to the cloudy blue versus that of the transparent blue color change.

Here ya go!

Habib thank you so much for responding so quickly! Yes it helps immensely!!

You're welcome!

So, to make sure I'm understanding what you're saying:

Cloudy Blue is the end point?

Yes

When I test, I do see the change to Purple. 2 or 3 more drops does change the color from Purple to a Cloudy Blue.

Correct!

 

[returnofsid]

So, now that I know, I'll need to retest...lol. It would seem that the end point is the Cloudy Blue, with no hint of Purple. As soon as you see Blue, instead of Purple, you're there!!

 

[krisfal]

Thanks for asking the question, need to go retest now . . .

 

[Boomer]

I did not know this was here :lol: But we did kinda solve it on the other chem forum It is cool to have Habib back in the game. He PM me last week or so he was coming back He is going to redo the instructions for us on the "clear" blue issue.

 

[returnofsid]

I did not know this was here :lol: But we did kinda solve it on the other chem forum It is cool to have Habib back in the game. He PM me last week or so he was coming back He is going to redo the instructions for us on the "clear" blue issue.

Glad to hear!! Re-wording the directions, may cut down on a lil' confusion...lol.

Also, really glad to hear that he's back in the game!!

 

[Frankie]

Looks like a good thread to subscribe to for future posts.

 

[Aquanaut]

This is a great thread for those new to the CA testing game.

Although, I preffer Elos since it clarifies the result w/ a re-check using a diluted "D" agent replacing the last known "C" drop. "C"=50CAL and "D"=10CAL. Example 1st test: 8C= 400CAL, 2nd test: 7C+2D resulting in 370CAL.