I tested the water of the shower/bath:
<0,01 mg/l NO2
but: 30 mg/l for NO3 :/
And also our rainwater:
0,2 mg/l for NO2 :(
but: 1 mg/l NO3
Now my question is: which kind of water should I use?
I have blue fairy, bumblebee and cherry shrimps in one tank and one betta in...