Elos CA Test Problem?

[patchin]

My tank isn't doing well and Tong came over to pick up a tank and did some tests on my water. Everything looked good except for my CA. His Salifert kit showed 330 or so and my Elos was 440. Has anyone else run into such a discrepancy? My test kit is kinda old. Could that be the problem? Any ideas?

 

[cwolfus]

Pick up another one. ;-)

I use Salifert.