Frustrated with Calcium Test Kits!!

[PirateLove]

HI RC! I do not know what to do about my calcium situation. Here are my results...

API- 480
Hanna checker- 438
API- Red Sea 380

None of these are even close! I will do all three tests again and post back the results but man... I used the hanna a few days ago and it read around 480 so I stopped dosing calcium and now I am just very confused on what to do.

Any suggestions? :uhoh3:

 

[Jone]

make sure your testing vials are clean and rinsed out well...make sure theres no reangent residue from previous test in vials..take your time and youll get it done right

 

[PirateLove]

make sure your testing vials are clean and rinsed out well...make sure theres no reangent residue from previous test in vials..take your time and youll get it done right

Thanks Jone. I always keep my vials soaked in citric acid or vinegar until I use them.

Looks like I solved my own problem. I had a new batch of Reef Crystals mixed up. Instant Ocean claims 455ppm at 1.026.

After measuring with Red Sea it only came out at 400
ApI was high at 470. So it looks like hanna will be just right if I do the test.

 

[disc1]

Thanks Jone. I always keep my vials soaked in citric acid or vinegar until I use them.

I wouldn't keep them constantly soaking, especially in citric. And definitely rinse the acid out really well before you do the test. A little bit of citric acid left in the vial will throw the test low. A good rinse is all they should need. You've got a test kit with 10 or 20 pppm maximum of precision at best. Even worse when you account for systematic error. We're not running a NIST lab here.