hi there MrLuigi, so voodoo juice is basically beneficial bacteria , so this one you can use throughout the grow. B52 is an additive with humic acid, and it's the same story, you can add it from the start. Just be very careful because they can work well together as well as be a bit too strong. they'll basically make the other things you are adding much stronger to the plant. That's why you should be quite careful if you use them at the same time . start small and increase them as the plant needs. For example if you have root problems use them both but if not , alternate them. Something like that. The good news is they dont change the taste of the product like the bud candy from adv nutrients. Hope this helps ! 🚀