yea that one sucks. I think (hope) it says shake 30 sec by itself then 1 min in test tube.Sorry if I missed it, but the only other anomaly I can think of is make sure you are doing the nitrate test 100% per the instructions, which includes shaking the crap out of bottle #2 for at least one minute prior to dispensing it, then shaking the completed test tube until your arm hurts. THEN wait 5min and read the results.
I'm probably off on the instructions a bit, but you get the basics. Performing the nitrate test is a common one for folks to get wrong.