pH
The optimal pH for nitrification is 8.0; with nitrification limited below pH 6.0.
HARDNESS
This is a measurement of the concentration of calcium and magnesium in the water.
TEMPERATURE
Increasing temperature can increase the rate of nitrification and nitrifier growth, and decreasing the temperature will decrease the rate of nitrification and nitrifier growth. Optimum temperature is about 25° C. Nitrification is inhibited at 10°C or less. ( Nitrobactor , which converts nitrite into nitrate, has been shown to be the first one to slow in growth rate when the temperature drops.) Please see the temperature versus MCRT graph in the wastewater section for a visual representation of temperature