Exercise 4: nitrogen compound - lab of the 26.02.2007

We measured the nitrogen compound concentration of the water with different test sticks. These stick, we had put into the aquarium water, announced a colour wich we compared with a colour skala on the packaging.
nitrat (NO3-): 0 mg/l (the sticks were run off 20 year ago)
nitrite (NO2-): 0 mg/l
ammonium (NH4-): 0 mg/l