on my mardel 5 in 1 test strip, the top square, which is for nitrates, is brown when I take it out of the bottle and brown after I dip it.
well brown is not an option on the comparison chart. I have bought a few bottles and they are both like this.
have any of you had this experience?
I recently bought a pack of the tetra test strips, and I'm pretty sure the nitrite and nitrate were swapped on mine. the color is wrong (no matter what concentration) for the test that's supposed to be in the same position, but seems to be about right for the one I suspect it was switched with.
Shrug, I've found the Mardel test strips to be accurate enough for their intended use: letting me know whether or not an issue might exist that needs further attention. I can't speak for any other type of test strip however as I've never used them.
Expired batches and *returned* batches tend to cause the most problems. Last time I was in line at my local chain store, a woman was returning one--she'd put the bottle back in the original box but admitted (when asked) that she'd used two of the strips. But, she said it was fine because she'd put them BACK in the bottle so all the test strips were still there. Seems she had the notion that once they dried out they could be used again.
Unfortunately, whether it's ignorance or apathy, plenty of chain workers will process a return without inspecting the item or asking if it's been used --and then let it get put right back on the shelf.
I've a liquid test for use during cycling for more accurate results and for fine-tuning/testing problems--but the test strips are handy to have around and I do use them on occasion. They're also much easier to slog into my kit--and hand over a few with a prev bottles chart--when I'm heading out to pull a newbies "but the pet store said!" impulse purchase tank back to a state where they've some hope of it surviving their learning process.
I hardly ever test my tanks so using liquid isn't that much work... Why use something that has a higher percent of being wrong? That seems like wasting time to me. If I'm going to take the time to test I want the most accurate test available. So for me its liquid only but to each his own.