I do not know if I need to pay attention to this? I did not do experimental phasing and I did not add heavy metal to my crystal nor there is selenium on my protein. I even don't know why I still get the anomalous signal.  

But from the detailed summary below I guess in my case it's not a problem?

                          ----------Summary----------

                              File name:                        P2_rejoutput.sca

                            Data labels:               I(+),SIGI(+),I(-),SIGI(-)

                            Space group:                                 P 1 2 1

                              Unit cell: 72.255, 46.617, 134.086, 90, 90.052, 90

                              Data type:                          xray.intensity

                             Resolution:                        49.1682 - 2.5855

                              Anomalous:                                    True

  Number of reflections (non-anomalous):                                   27184

           Completeness (non-anomalous):                                  95.42%

            Number of reflections (all):                                   38285

                     Completeness (all):                                  69.98%

                 Anomalous completeness:                                  42.34%

  Completeness (non-anomalous) is the completeness of the data after merging

  Friedel pairs.

  Completeness (all) is the completeness of the data before merging Friedel

  pairs.

  Completeness (anomalous) is the completeness of the anomalous data. The

  anomalous completeness is calcluated by dividing the number of measured

  acentric, Bijvoet mates by the total possible number of acentric indices.

  Completeness (non-anomalous) should be used to determine if there is

  sufficient data for non-anomalous purposes (refinement, model-building).

  A value greater than 90% is generally desired, while a value less than

  75% is considered poor. Values in between will provide less than optimal

  results.

  Completeness (anomalous) should be used to determine if there is sufficient

  data for anomalous purposes (phasing, finding anomalous atoms, refinement

  of anomalous occupancies or scattering factors). A value greater than 80%

  is generally desired, while a value less than 50% is considered poor. Values

  in between will provide less than optimal results.