The answer is yes to all of the above questions.

However, it may not be necessary to add EMDROPS, in case your drinking water already has good levels of calcium and magnesium.

If you use a reverse-osmosis filter, a distillation system, a water softening system, or if you use purified bottled water, your water will not have any significant level of calcium and magnesium. Regular consumption of such waters is not advisable, since this may lead to calcium and magnesium deficiencies unless you eat a wonderfully perfect diet, and such deficiencies can cause many health problems.

Therefore, the best use of EMDROPS as a water enhancer is in the following cases:
a) distilled water
b) reverse-osmosis filtered water
c) softened water
d) purified bottled water
e) whenever your tap or well-water is naturally low in calcium and magnesium and
f) whenever you want to increase intake of essential minerals, particularly calcium & magnesium.