shake well before using

sooooo, i just realized a few days ago, that my bottles of nutirents from FF say to "shake well before using." Something i haven't been doing up until a few days ago. When i shake, the liquid gets far darker, and nastier looking. Which means i think it's pretty important to shake well before using. but enough to cause a deficiency?

How important is it to shake before using?

Its important, kinda like shaking chocolate milk. Ask any 5 year old if shaking the chocolate milk is important.