This is a curious question.

Considering we condition our water to dissolve the heavier toxic elements in our water that toads can't digest via whatever solution you've been recommended.
I was considering the idea that we could dissolve vitamins into our water as well, for example vitamin B, Calcium, or maybe Magnesium. clearly this is a far stretch to assume our very primal counterparts can handle our human dietary needs, but is it safe to say that some vitamins might be helpful if not beneficiary to our amphibians health?