Antos, I finally got a few minutes to test my water.
I draw the water through the site guage, filling to the 25ml mark
add 25-30 drops of the sulfuric acid solution, swirl to mix
add the reagent one drop at a time swirling until the purple disappears - you should see a vortex that dissipates
continue adding one drop at a time and swirling until the solution turns pink and persists for one minute
It took 52 drops for the solution to turn and persist
I'm plenty good on nitrite
The trick is to swirl each drop until the color disappears, it is easy to overload with reagent.
I hope this helps.