Salifert Aging Question

[Justdrew]

I have a Salifert Calcium kit that I have had for a year or more. It's expiration was 9/2019. I was consistently getting CA measurements around 430-440 with this kit. I could see that I was about to run out, so I ordered a new Salifert kit. The new kit's expiration is 11/2020. With this new kit I get a 500+ reading on the same water sample. The kits are slightly different, where the older one had black and white instructions, and required 8 drops of part 2. The new kits has color instructions and requires 10 drops of part 2.

My question would be as a kit ages would it tend to read lower or higher?

I will have to come up with a way to confirm, either through a LFS test or purchase a different kit.

Thanks
Drew

 

[Randy Holmes-Farley Verified Community Expert]

My question would be as a kit ages would it tend to read lower or higher?

There's no simple answer to that. Sorry.

 

[Justdrew]

So if I am getting 490-500 on freshly mixed 35ppm Reef Crystals, it is probably safe to say the new kit is within range. My tank is somewhere in the 500+ range then.

Thanks again!

 

[Randy Holmes-Farley Verified Community Expert]

So if I am getting 490-500 on freshly mixed 35ppm Reef Crystals, it is probably safe to say the new kit is within range. My tank is somewhere in the 500+ range then.

Thanks again!

Luckily, our aquaria are seem pretty insensitive to calcium levels within a range from about 400-550 ppm.