Thx a lot! I guess I am just a little inpatient now after 4 weeks.🙂 I will sit and wait until my little bacteria fiends eat up the NO2. Do u think I should do a water change now or better wait? ThxHi Kai,
that is a common phenomen within new tanks. The tank starts to cycle and bacteria for nitrification start to develop. Since your tests don't show minimalistic readings, you don't notice them, but there is a bit NH4 and NO3 for sure. This NO2 will go away soon and afterwards your tank is ready for fish and other animals 😉 In germany, we call this a nitrate-peak. Don't know if thats a thing here too.
Kai