So I have the newest version of the test strips. I compare them against my Tetra ones. Also, when I didn't get results, I tested with the API master kit (Nitrates only). I do get color change, but not much. According to the API, and Tetra, my Nitrates are higher. Around 40ppm. But with the Co-Op strips, it only shows 10-20ppm. I follow the directions on the bottle. I have tried a few different times, a few different tanks. But it just doesn't register as high as the others. Could it be my batch of strips? I've been very careful not to let any water or dampness get into the bottle, so it's not that. Ideas?