hi there toke with hope Improper plant nutrition can often times be the cause of many plant problems. One of the most common ways this occurs is through improper acidity of the nutrient solution, soil, or water. Most tap water is TOO HARD, meaning it has a pH of over 7.0, and usually up to the 8.0 range.
Purified water and drinking water you buy at the store has a pH of 7.0 (pH neutral) and <20ppm. Even this is a little too high for plants, which need water to be a little softer (more acidic) to thrive. pH around 5.5 for hydro and 6.5 for soil... is key to the success and survival of your plants While using harder water will work out, it won't work out as well, and could cause serious problems. Same goes for water that is too soft, although that is less rarely the case. good luck and take care !