Petre Using a RO +DI filter I get 0 TDS water in a 5L container, this takes few hours, container is not sealed so it has contact with air during this time
It’s a good idea to use a container that is as sealed as can be given you are pumping eater into it….
There’s nothing special about distilled vs di water. Distilled may be more or less pure depending on how many times it has been distilled and with what equipment e.g a lab distiller made of glass that continuously distills would output higher purity distilling 4x than my counter top stainless steel distiller that distills 1x and lets the water condense in the steel pipe. DI won’t remove everything from the water (just ions) so any impurity that doesn’t have a charge is left, which is probably where the idea of the RO stage comes in.
Pure water is non conductive and has a pH of 7 which falls to about 5.8 after a few hours exposure to air as it readily absorbs CO2 from the atmosphere. Cold water is much better at dissolving CO2 (and O2) than warm water. If water from a distiller is collected and sealed while it’s still warm maybe you can limit how much gas it absorbs compared to using the same collection and storage method with RO/DI water production, though as RO/DI doesn’t boil and condense the water, it’s going to have some dissolved gas from the start….Adding bicarbonate will raise both pH and alkalinity so the pH change itself isn’t too much of a concern.
