Just started a grow in a location with around 200 ppm out of the tap. After reading the local water analysis, I have come to the conclusion that the tap water contains high levels of calcium which in turn is locking out the magnesium and causing purple stems on all of the strains I am running. Though I am a very experienced grower, I have never been faced with this issue before. I have read many times about blades adding epsom salt to there hard tap, just not sure how this solves the problem of calcium toxicity. I know that Cal and Mag need to be given at an equal rate to avoid locking out the Mag but how do you find the correct dosage for individual tap levels? Any help from pros that are currently growing with hardwater would be appreciated, I refuse to begin flower with these levels of calcium, as I am a perfectionist but this is not my level of expertise.