You are using the old NT labs kit. When I used it my ammonia readings were at zero too. On the new kit, traces show up. I did a comparison across six tests using the old and new kits: there were difference to all - particularly Ph.
Great Video. I use the Hanna because I always struggled with the test tubes. Trying to get an accurate reading with the tubes varies so much with different light and when there is a very thin line between 0.2mg/l and zero you can't afford to misread. Great Channel and here's a new Sub.
I've just noticed the flashing digits is because you haven't done the timer before the reading. It runs through the time settings and automatically shows the reading at the end. I also noticed that you need to check the Chemical Formula as the actually reading for Nitrite comes as NO2-N, NO2- & NaNO2. I think you need to change it to NO2- for just Nitrite. Also the reading for Nitrite is Micro Grams per litre not Milligrams, so a reading of 17 Micrograms is 0.017mg/l which is brill. Run the Ammonia again and Zero the vile then run a sample with the timer and wait and it should work out right.
