I have done some internet research but I did not found useful information. The burgundy mixture (copper sulfate + sodium carbonate) was sprayed on vineyards, but I think not nowadays. My doubt is about the possible formation of copper carbonate that in my understanding has a low solubility in water and thus, maybe, a lower efficacity against downy mildew. All this because I would like to answer the following question: does water low in carbonates is a better bet for copper treatments on organic vineyards? Or, at the end, does not make difference against high carbonate waters? Lowering pH is all I need to use alkaline waters?