Hey guys, this is my first post here and a strange problem.
I Have a 30 Gal Hexagon/flatback tank.
I originally had 12 fish in the aquarium and now im down to seven.
Ammonia level is reading 0
Nitrates is reading 20
Nitrites is reading 0
Alkalinity is 80 (Moderate)
Ph is 7 (Neutral)
Tank...