Tap water may be of any quality. Depending on its source it can be relatively free of mineral content or laden with many minerals. In order to find out the quality of the tap water, contact the local water supplier. Their report will show total amount of dissolved solids, individual minerals, the pH, alkalinity (a measure of the amount of calcium in the water) and pollutants. You will see nitrates, nitrites and phosphates listed. It is truly interesting.
In one area of California, San Francisco’s East Bay, the electrical conductivity (EC) of the water, ranges from 30-50. Four hundred fifty miles south in Los Angeles, the EC is 450. This affects how water is fertilized and what nutrients are required. For instance, the San Francisco water is too pure. It doesn’t have enough calcium to stabilize it and it can vary widely in pH as plants withdraw minerals from the solution. The Los Angeles water already contains significant amounts of various minerals, sometimes too much, so the fertilizers must be adjusted or the water purified before using it.
Dehumidifier water is very pure and has a negligible EC. It should not be used by itself unless calcium and magnesium are added to increase alkalinity. However, it is excellent to use to dilute high EC water.
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