Corrections are made for salinity and particulate matter, then the bacteria are exposed to the sample solution depending on the methods of the particular test. The light output of the bacteria is measured using a photometer after five and 15 minutes from exposing the bacteria to the samples.[12] The light measured directly correlates to the toxicity of the sample, producing data that allows for the calculation of EC50 or IC50s, or other ECxx and ICxx values.[14]