Acidic distilled water caution.

[Mad Scientist]

Hi people! One thing I've noticed with distilled water - it can often be acidic! Pure water is defined by conductivity not pH (acidity or alkalinity) so water can be "pure" from a distiller yet too acid to drink! It varies regionally. One test you can do is to add an indicator to a sample of your water. You can either buy it from an aquarium shop or make your own indicator: boiled red cabbage water! Add some cabbage water to your sample. If the water is neutral, which is what you want, the sample will become green. Yellow/ green is tolerable.Wouldn't drink it if the indicator is any other colour. You can use the water for other things of course! Hope this helps.

[spare tyre]

will waiting for it to oxidise help? additional Oxigen combines with the hydrogen, which is what makes a solution an acid. boiling breakes some of the bonds between the H and O, that's the bubbles, released O2. just thinking logically here, pass the water between 2 containers for a while improves the taste, perhaps this is because of oxigenisation? feel free to shoot down my science lol

[duffmanj]

Your logic sounds pretty good to me! I use reverse osmosis (RO) water for my aquariums, pure RO can cause PH swings especially if a tank is planted. During the day when plants are releasing oxygen, the PH increases (to a point) and during the night when this oxygen generation stops the PH can plummet. The thing that stops it from doing this is the KH buffer, which is the carbonate hardness of the water. RO or distilled water contains very little of this, which causes the wild PH changes. My advice would be to not only oxygenate it, but add some bicarb of soda to stabilise the levels. I think that 1 teaspoon per 5 gallons (22ish litres) might be about right.

Be aware that too much of this could cause health problems in some people (I think those that suffer from calcium deficiency?) so do your research first just in case!

[Holomon]

Some distilled water can be slightly acidic, but not enough to cause you harm.
It becomes acidic by exposure to the atmosphere because it absorbs carbon dioxide.

You'd have to be on some sort of medication that affects stomach acid production for it to be a problem, and even then only if it was at a relatively high acidity level.