API and Salifert Differ by a lot

[jcsprofile]

Hello everyone! I have been using the API Reef Master test kit and I am almost out of the calcium reagent. I decided after doing some research that Salifert may be better than the API kit so every time I test, I am using both to get used to the new kit (I’ve only tested 2 times) but both read drastically different! My API is reading 360 and my Salifert is reading at 440 and I do not know which one to trust!

 

[Acros]

Is the gap between the test kits same every time?

 

[Dunc]

I have a real hard time distinguishing colors, so I bought Hanna Checkers. No more guessing.

 

[Spare time]

Test them against freshly mixed saltwater with a known calcium level at x salinity

 

[jcsprofile]

Is the gap between the test kits same every time?

Both times it has been a difference of around 80.

Test them against freshly mixed saltwater with a known calcium level at x salinity

I just tried that and the API test kit seems to be closer to what the box said! Thanks for that tip, might have to stick with the API.

 

[Acros]

If the difference is similar, you don’t have anything to panic. Just stick with one. Neither are accurate measures, but both seems reliable. Stick with one and look for upward and downward trends rather than actual measures.

 

[dadyoj21]

I recently received a new salifert calcium test kit and used it to check my systems and got unusually high results. I still had some left in my old kit and ran the samles with the old kit.

The new kit is different and skips reagent 2 and both my systems were 60-70 ppm higher with the new kit. I believe the new kits read way high as I have been using the other version for many years with no problems.

I have found several threads with calcium problems and the common variable is the new salifert calcium test kit.