TLDR; It's never a bad idea to have alternate (backup) test kits.
PSA - first, a shout out to @KGV for his nitrite concentration thread. Had he not posed the question I might not have decided to test my nitrites, which for convenience led to me figuring well, I have my Red Sea Marine kit out anyway - I might as well test my ammonia and nitrate levels as well. Short version is that my ammonia was fine (0.0), nitrites were about where I expected (0.2) - but my nitrates were significantly higher. They'd climbed to about 10ppm 2 weeks ago from the usual 3-5ppm and I was under the (mistaken) impression that I'd successfully dealt with it since they were testing back down around 5ppm again.
The short version of the story is that I'd been using another reliable test kit from another manufacturer, and in the process of cleaning and drying everything off I'd managed to place a wet lid on a dry bottle of reagent. Despite quickly realizing my error, a few drops of water did fall into it. I figured it's just water, so I scooped out and discarded the damp portion, let it air dry for a bit and resumed using it without giving it a second thought. Until today. After the elevated nitrate test I retested using the nitrate kit I'd been using for the past few months. And it read normal. Fortunately, I had a new (unopened) test kit from the same manufacturer and ran it - and the nitrates came back elevated as well (pretty close to the Red Sea kit). Through a process of elimination I was able to determine that I'd managed to screw up the reagent in question and my nitrates (and fortunately only my nitrates) have been higher than I would've liked.
So as I finish writing this I'm off to dose some NOPOX and perform a small water change along with a reduction in feeding for the next week or so until things get back on-track. So it just goes to show that whenever you have really good or really bad water parameters it never hurts to double-check this with a different or unopened test kit.
PSA - first, a shout out to @KGV for his nitrite concentration thread. Had he not posed the question I might not have decided to test my nitrites, which for convenience led to me figuring well, I have my Red Sea Marine kit out anyway - I might as well test my ammonia and nitrate levels as well. Short version is that my ammonia was fine (0.0), nitrites were about where I expected (0.2) - but my nitrates were significantly higher. They'd climbed to about 10ppm 2 weeks ago from the usual 3-5ppm and I was under the (mistaken) impression that I'd successfully dealt with it since they were testing back down around 5ppm again.
The short version of the story is that I'd been using another reliable test kit from another manufacturer, and in the process of cleaning and drying everything off I'd managed to place a wet lid on a dry bottle of reagent. Despite quickly realizing my error, a few drops of water did fall into it. I figured it's just water, so I scooped out and discarded the damp portion, let it air dry for a bit and resumed using it without giving it a second thought. Until today. After the elevated nitrate test I retested using the nitrate kit I'd been using for the past few months. And it read normal. Fortunately, I had a new (unopened) test kit from the same manufacturer and ran it - and the nitrates came back elevated as well (pretty close to the Red Sea kit). Through a process of elimination I was able to determine that I'd managed to screw up the reagent in question and my nitrates (and fortunately only my nitrates) have been higher than I would've liked.
So as I finish writing this I'm off to dose some NOPOX and perform a small water change along with a reduction in feeding for the next week or so until things get back on-track. So it just goes to show that whenever you have really good or really bad water parameters it never hurts to double-check this with a different or unopened test kit.