How and What to Flush with in DWC?

This is my first time flushing with a DWC system. I wanted to know if you can just flush for ten days with water, or should i buy a flushing product like Final Phase? I read that flushing products contain things that suck salts and metals out of the bud so it taste fresh. I would like to flush with just water but if a small bottle of Final Phase is the difference between regular bud and dank nugz then ill go with a flushing product!!

Nothing will remove anything that your plant has already taken in. Flushing at harvest time is a waste of time.

My mind agrees.but my lungs beg to differ!

I have heard just using dilute strength nutes (15-25% strength) for the last week acts like a final flush. I dont know how true it is, but apparently the plant uses up any excess nutrients it has stored.