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-   -   ALERT: Salifert Calcium test instructions have changed (http://www.canreef.com/vbulletin/showthread.php?t=125429)

Myka 02-04-2018 03:59 AM

ALERT: Salifert Calcium test instructions have changed
 
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 02-04-2018 04:35 AM

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

Quote:

Originally Posted by Randy Holmes-Farley
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 02-04-2018 02:39 PM

Thanks!

Frogger 02-04-2018 10:06 PM

Quote:

Originally Posted by Myka (Post 1023938)
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 02-05-2018 12:59 AM

Quote:

Originally Posted by Frogger (Post 1023964)
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 02-08-2018 10:49 PM

Thanks Mindy !

straightrazorguy 02-09-2018 02:16 AM

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

Myka 02-09-2018 03:32 AM

You're welcome guys. :)

FlamesFan 02-09-2018 04:38 PM

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

Myka 02-10-2018 04:38 AM

Quote:

Originally Posted by FlamesFan (Post 1024141)
Myka would you mind linking the R2R thread with randy's comments?

https://www.reef2reef.com/index.php?threads/336775/


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