That change (in V3) to a higher level of magnesium seems like a good idea. I'd normally be asking about what that does to the calcium:magnesium ratio - but I'm using high-Ca tap water, so I doubt such a question would be all that relevant to my situation.
I assume that this product - or these products, since there have now been three different versions - are compatible with my water source. Am I likely to be correct? I believe that what I'll be getting (from a very kind individual, not from the nutrient company) will be the "V2" formulation.
Is anyone using this with autoflowers in soil? Is anyone using this with autoflowers in perlite hempy?