Need help with checkers

[Terri Caton]

Hi, I was having something funky happening in my tank but all my parameters read as they normally do. I took a sample to my LFS and their Ca and Alk readings were very different than mine.
Me - Ca 460 Alk 8.0
Them - Ca 350 Alk 6.0

Then I took a water sample (same water) to another LFS.
Them - Ca 250 Alk 2

What the heck?! Obviously the 2nd LFS is a crappy one (I never go there but it's the only other one in town)

Is there a reference solution to use on the checkers to see what it actually reads?

Thanks

 

[Shirak]

There are reference solutions to see if the checker is reading properly. But that doesn't rule out an issue with your preparing and using the checkers. I don't have the Ca one but hear it is notoriously difficult to get an accurate reading due to the small sample size and dilution step. The Alk one should be fairly straight forward. Are you cleaning the vial of all finger prints and inserting it in the same orientation between step one and two?

 

[lafarrow]

There is always that old stand by the icp test.

 

[Terri Caton]

There are reference solutions to see if the checker is reading properly. But that doesn't rule out an issue with your preparing and using the checkers. I don't have the Ca one but hear it is notoriously difficult to get an accurate reading due to the small sample size and dilution step. The Alk one should be fairly straight forward. Are you cleaning the vial of all finger prints and inserting it in the same orientation between step one and two?

I've been using them for over a year so I can basically do it in my sleep. I'm positive I'm performing the tests correctly. It's only recently that a few of my corals are looking worse for wear and my parameters with my checkers reads the same.

And that's my question to Hanna. I can't find a reference solution for either Ca or Alk

 

[Terri Caton]

There is always that old stand by the icp test.

Yea, that's my next step.

 

[Shirak]

Fresh reagents? Particularly for the alk test. What salt are you using? You could try running the tests on a new batch of salt water and see if the numbers are in the range for the salt mix. Or get some reference solution and run the tests on that. I think Fauna Marine has one on the market.
I would pick up a secondary test kit for alk and Ca. Something like the salifert would be good. I would not necessarily just trust the lfs readings either.

 

[Opus]

I've been using them for over a year so I can basically do it in my sleep. I'm positive I'm performing the tests correctly. It's only recently that a few of my corals are looking worse for wear and my parameters with my checkers reads the same.

And that's my question to Hanna. I can't find a reference solution for either Ca or Alk

Reference solutions:

Marine Alkalinity (dKH) Checker® HC Calibration Check Set - HI772-11

The Marine Alkalinity (dKH) Checker® HC Calibration Check Set - HI772-11 provides a stress-free, straightforward way to ensure your handheld colorimeter is working properly and providing accurate alkalinity measurements.

www.hannainst.com

Marine Calcium Checker® HC Calibration Check Set - HI758-11

The Marine Calcium Checker HC® Calibration Check Set - HI758-11 provides a stress-free, straightforward way to ensure your handheld colorimeter is working properly and providing accurate calcium measurements.

www.hannainst.com