View Full Version : Salifert CA test kit expired?

12/23/2011, 10:47 AM
i have used salifert CA and ALK about a year, bought them from BRS. from my log, the CA dropped from 440 to 350ppm from Oct to Dec. In addition, a massive CA precipitation was observed in tank. I thought my Kalk was dosed too fast by aqualift pump in my 34G tank. Never checked the test kit.
Yesterday, I bought another CA test kit from BRS, it has the same expiration date (09/16) but it seems a new version. The tank water was 410ppm instead of 350ppm. I measured twice with both kits, they gave me the consistent reading, 60ppm difference!!! To confirm it, I went to LFS and bought a API, it was very close to 420ppm.

now my concern is, is my "bad" test kit always wrong or just got wrong from Oct when I saw the CA dropped. If not, does it mean the test kit can lose the accuracy from any day? It is scary.

12/23/2011, 11:54 AM
The only way to tell is going to be to check the kits against something with a known calcium concentration. The truth may be that both kits are off and the real answer lies somewhere in between. That doesn't mean they are useless, it just means you need to do a little math.

Look at this thread: