calcium level reading

larrynews · Jul 10, 2021

so i am wondering what my TRUE calcium level is, my Hanna checker say one thing, my salifert says another and my pinpoint something different so i borrowed a Hanna checker from someone and theirs was even a different reading than mine. does anyone live by the movie tavern area on 92 and sandy plains that has confidence in their monitor/testing system that i could find out which if mine is correct so i can go by that one .
thanks

Steve Burton · Jul 10, 2021

What readings are you getting? The Hanna reading accuracy is + or - 6% at 77° F so for a Calcium content of 425 the meter reading would be between 399.5 and 450.5. I have a Hanna Calcium calibration check sample if you're ever in my area and would like to see if your meter is within the 6% accuracy range.

ichthyoid · Jul 11, 2021

The Salifert is +/- 10 mg/L
The Pinpoint is +/- 2% (so ~8+ mg/L, after calibration-?)

So, your Pinpoint monitor should be most accurate, assuming you recently calibrated.
Your Salifert should be next most accurate. Then, lastly your Hanna is least accurate.

Fwiw, Red Sea has a ‘high accuracy’ kit that states +/- 5 mg/L

I would take samples of both fresh mixed & tank water to a LFS & get a 2nd opinion, just to be sure.