Student or Learner
This is an extract from a manuel and i am not sure what "mature" means in this sentene.
- ammonia and nitrite concentrations should remain immeasurable in established aquaria with mature biological filtration,
Please help me.
Last edited by paris 06; 10-Feb-2011 at 20:15.
I am not a teacher.
It means that the living things that clean the water have been there long enough to have formed a stable community.