Perfect water profile

As Grannie mentioned. It depends if you are growing in soil or hydro. Water for plants is a precursor as opposed to being primary ingredient as it is in beer. You won't find brighter hop/terpine flavors by altering water chemistry like you would with beer. For most, simply keeping the pH within the proper range is most important. Then there is EC which is also a very basic measurement and about the extent of "building water".

Well, there's probably nothing that will ever approach the label of "perfect" in cannabis... there are just too many variables when dealing with a living organism such as a plant... BUT there are guidelines for EC readings when you're growing hydroponically... this is a fairly good article on the subject ... just understand that there can be some wiggle room depending on whether you're growing a photoperiod or autoflower or clone... but understanding the concept here will give you a good head start on tackling the issue... https://www.humboldtseeds.net/en/blog/understanding-electroconductivity-achieve-bigger-yields/ Good luck!