Final answer:
Ionic compounds (salts), excess nitrogen, and bacteria can cause a large conductivity reading.
Step-by-step explanation:
A large conductivity reading can be caused by ionic compounds (salts) which can dissociate into ions in solution and enhance the ability of the solution to conduct electricity. Examples of ionic compounds include table salt (NaCl) and magnesium sulfate (MgSO4).
Excess nitrogen can also increase conductivity in water. Nitrogen compounds, such as ammonium nitrate (NH4NO3), can dissociate into ions in solution and increase conductivity.
Bacteria can indirectly affect conductivity by producing waste products that can ionize and increase the concentration of ions in a solution, thereby increasing conductivity.
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