Hi all,
but I'd assume it would be impossible to produce o tds water if it was exposed to the atmosphere?
While I was answering
@Oldguy's question I found the figures for this:
........As distillates are open to the atmosphere before measurements can be made, the value of conductivity is really much less (down to 10 times) than it is really measured. Any ultra pure water in contact with the atmosphere has a conductivity of 1-2 microS/cm and a pH of 5, due to the small amount of CO2 (0.5 ppm) absorbed from the atmosphere.............
As an aside I wonder about the quality on DI water for car battery maintenance, miss real distilled water.
A few people have dipped a conductivity meter into RO water they've got from an LFS etc. and found conductivity readings in the hundreds, presumably because the unit wasn't working and nobody had checked. The lab units are <"
Veolia ELGA DI units"> and they have all sort of alarms on them should the conductivity rise.
The advantage of distilled water is that it is always a known entity, because steam distillation doesn't have many moving parts (just the steam really).
We still have some stills plumbed in, (like <"
the one below"> ) but we don't use them any more.
When we used distilled water, rather than DI, the water used to have a slightly higher conductivity , partially because the tap water is very hard (about 18dKH and 650 microS) and you only need very minor contamination to increase the conductivity. We used to get through a
lot of acid cleaning the still up every week.
We also used to get through a few stills because the water pressure wasn't very consistent and if pressure dropped enough the cooling water wasn't sufficient to avoid breaking the glass. The other problem is that you need (used to need?) a license to purchase a new distillation unit.
cheers Darrel