Removal of the residual hypochlorite or chloramine from water to allow its use in fish culture. Charcoal is used frequently because it removes much of the hypochlorite and fluoride. Charcoal is inadequate for removing chloramine.
A biochemical reaction in which nitrate (NO3-) is reduced to NO2, N2O, and nitrogen gas.
Food regularly provided and consumed.
The amount of elemental oxygen, O2, in solution under existing atmospheric pressure and temperature.
The residue of all dissolved materials when all water is evaporated.