Can you do the API Nitrite test wrong?

[pookawolf]

I started cycling my tank almost 2 weeks ago with eco complete. After 4 days I was getting nitrites....everything seemed to be progressing and today the nitrites appeared to be lowering (the color on the API test went down from 5+ to between 1 and 2) but the nitrates didn't seem to be shooting up like I had expected. On a whim I decided to test using the tetra dipstick test we got (I was desperate for a kh gh test) and it showed the nitrites over 10ppm. I decided I was going to do a 50% water change any way just to shake things up (try to get the nitrites into detectable levels to try to monitor them).

When I did the 50% water change the Nitrite API test actually showed higher levels...is this possible or am I doing the test wrong?? The Nitrite on the Tetra test went down but is still 10ppm +

Should I do another water change tomorrow, this time maybe almost 100%, to try to get the nitrite down to detectable levels??

[librarygirl]

Hm, the nitrite test is hard to get wrong but it's possible. Do you shake the bottle before the test? I usually shake all of mine for a few seconds (except for the nitrate tests which requires longer shaking)? What is the date of the test bottle (on the bottles, there are some numbers; the last 4 will give you the date of manufacture in month/year, such as 0910 is Sept 2010). I think the tests last about 2-3 years depending on test but it's good to double-check).

Do the drops turn purple as soon as you put them into the tube and then get lighter, or do they go in blue and then darken to the 1-2 range? If they go in purple and then change, your nitrites are so high that the test can't detect them.

I would do a very large pwc as you said and try to get them readable and then see what happens.

[pookawolf]

Thank you for responding. I haven't been shaking any of the bottles (except for nitrate 2). They are all from March of this year. They definitely were going in dark purple and getting lighter. It looks like I have an almost 100% water change (or more) on my morning to do list!