>Water in is at 149, RODI water out 8.<
That's not RO/DI water. Should read zero. My opinion, take it for what it's worth, is that RO/DI water could be stored for decades. The ONLY thing that will happen to it is that over time some of the components of whatever it is in will dissolve into the water. If plastic, that means that trace amounts of plastic components will dissolve into it. Not enough to matter. Trace amounts of bacterial will also grow in it, but they will mostly be living off of the nutrients from the plastic or whatever surfaces are in the water. I would have no hesitation in using the water even if there was a slight smell of mildew (this again assumes that it was DI water with a TDS of zero to begin with). Also, you should understand that the water will absorb carbon dioxide from the air until it is in equilibrium with the carbon dioxide content of the atmosphere, which, thanks to our industrial society, gets a little higher every year. When the CO2 dissolves in the water it creates small quantites of carbonic acid and will depress the pH of the water, again, not important, water is still fine, but might not read 0 anymore on your TDS meter (might read 1-2 maybe at most I think).
