Are there many blank cells in column 6 of Alpha that you could do without copying over?
Perhaps changing:
Sheets("Alpha").Cells(j, 6).Copy Sheets("Reversion").Cells(i, 6)
to:
Sheets("Reversion").Cells(i, 6).value=Sheets("Alpha").Cells(j, 6).value
but the red font won't get copied across.