Ideally, the end product of distilled water would be the same as the end product of RO... but since the distillation process involves plenty of contact with atmospheric gases, which become dissolved in water (the levels depend upon the temperature of the water and will change over time as it sits), distilled water DOES have substances in it that are not H20.
Dissolved Oxygen, CO2, and N2 are present in distilled water, adn go into various equilibria in the solution.
However, CaCO3 (limestone), which is very very common in tap and surface waters, is removed, since it cannot vaporize at water's boiling point, which brings us back to why you need CalMag if you are running any type of purified water.
stinkyattic Reviewed by stinkyattic on . calmag plus how important is calmag plus if you are using distilled tap water, what effects will it have on my plant if i dont use it? Rating: 5