ALERT: Salifert Calcium test instructions have changed

[Myka]

Just an FYI for those of us who have done the tests enough times to not read the instructions anymore...

The Salifert Calcium test kits with an expiry 8/2022 now require 10 drops of Ca-2 rather than 8.

However, since both the Ca-1 and the Ca-2 are provided in excess, you shouldn't see much or any difference in the results.

[Myka]

I found a thread on Reef2Reef discussing the new instructions, and Randy Homes-Farley explains why you won't see much difference:

CA-1 is a dye the binds calcium. It is a different color when bound to calcium and when not. The amount is not critical except to provide enough color. It is a weaker binder of calcium than the reagent in CA-3. Less of it may actually give a sharper endpoint, but may be harder to detect visually.

Ca-2 solution is a hydroxide solution to precipitate magnesium hydroxide and prevent it from being detected. The amount of it is not important as long as there is enough to precipitate the magnesium.

The titrant (CA-3) is a strong calcium binder (e.g., EDTA, but I'm not certain what exactly they use). As it is added, it binds up calcium. Eventually, the only calcium left that is not already bound to the CA-3 reagent is bound to the dye. At that point more added CA-3 strips away the calcium from the dye, and so the color changes as the dye transitions from calcium bound to free dye.

Since Ca-2 precipitates Mg, then maybe 8 drops isn't enough for people with higher Mg levels in their tank??? Maybe that's why the change?

[FlamesFan]

Thanks!

[Frogger]

Just an FYI for those of us who have done the tests enough times to not read the instructions anymore...

The Salifert Calcium test kits with an expiry 8/2022 now require 10 drops of Ca-2 rather than 8.

However, since both the Ca-1 and the Ca-2 are provided in excess, you shouldn't see much or any difference in the results.

Does this mean if we have old salifert test kits that we should be using 10 drops?

[Myka]

Does this mean if we have old salifert test kits that we should be using 10 drops?

Not sure what the official recommendation is, but it sounds like that wouldn't hurt. Try both ways? I tried both ways (with the new kit that says 10 drops), and I got the exact same reading. Mg in my tank is about 1300 ppm.

[gregzz4]

Thanks Mindy !

[straightrazorguy]

Thanks for the heads up, Mindy. I still have an 8 drop batch.

[Myka]

You're welcome guys. :)

[FlamesFan]

Myka would you mind linking the R2R thread with randy's comments?

[Myka]

Myka would you mind linking the R2R thread with randy's comments?https://www.reef2reef.com/index.php?threads/336775/

[gregzz4]

Mag kit instructions have changed

http://www.canreef.com/vbulletin/showthread.php?p=1028369#post1028369

[corpusse]

The ALK changed twice, to 2 drops then back to 4 i think.

The only annoying part about these changes (all of them) is they don't notify at all. A lot of people have been using these for years and years. Now everytime I test alk I have to stop myself from adding 2 more drops. A sticker on the boxes saying "new instructions" would have been nice.

[gregzz4]

I haven't used it yet but my spare Kh kit 10-2022 has a piece of paper taped inside the lid "test kit instructions have changed" and it states 2 drops

[tang daddy]

My alk reads 2 drops but the newest ones are back to 4 drops... never assume...
The new test kits also have a different plastic card vs the old paper ones.

[gregzz4]

My alk reads 2 drops but the newest ones are back to 4 drops... never assume...
The new test kits also have a different plastic card vs the old paper ones.

I'll start a new Alk thread ...

http://www.canreef.com/vbulletin/showthread.php?t=126425

[Galizio]

This is weird. I have a salifert Ca test with expiry date 02/2022.
When tested the water last week my Ca was a 475 so decided was to high for my liking. Turned off the dosing pump and tested for a straight 6 days , some of the days even twice. Today I even try the new instruction after firs reading was 470, and second reading was 475.. all week Ca was fluctuating from 475 to 465 without even dosing. I keep dosing alk and mag and value are stable at 7.3 and 1245. But what bug me is the Ca. I dose the new formula AF component where Ca and Mag are not mix together . I

[gregzz4]

I just tested with the last usable amount of an 8-drop kit; 415
For poops and giggles I tested with a new 10-drop kit; 440 - what the ... ?
Tested again and got 430. Exp. 08-2022

I've always found their Ca kit to be consistent so don't get it.

[Myka]

You guys are demonstrating exactly why they changed the instructions. :D Some tanks will get the same reading on both kits though.



For the calcium kit, magnesium interferes with the results, so I suspect the cause for some tanks to read the same and other to read higher on the new kit is because of Mg interference (or not).


The same rings true for the KH kit - on most tanks you can use anywhere from 2-5 drops of the indicator and it won't change the results, but on some tanks it will change the results which is the reason for their changes. I'm not sure what is interfering in the KH kit.


I'm not sure of the reason for the change in the Mg kit. The time to swirl is so the calcium has time to be bound out of the solution so it doesn't interfere with the Mg reading.



The colored drops/powder in the kits is an indicator dye, and as long as there is a minimum amount of indicator in the test compared to the element you're testing, then it doesn't matter how much of it you use until you get to the point where you're diluting the test with the number of drops. Haha!