first off please dont get me wrong, regardless of what medium is being used that is a very good article for anyone.
Scott: I have always flushed for only the last week with plain water but this next run I am going to try the 2 weeks and see what a difference it makes. The only dark period I have ever used is 36 hours between veg and flower, that being said I will also be trying the dark period before harvest to see the results.