High pH RO/DI water

[Tink]

So, here's my current issue.... I have well water with a crazy low pH (around 5), and thus must achieve my RO/DI production a little differently. What I do is produce and store my RO in an aerated container for a few days prior to running it through my DI. The new DI water I'd then stored in a non aerated container until used.

 

The issue is that the resulting DI water from this process has had a rather high pH for purified water (somewhere around 9+). It actually spikes my tank pH a tad when I top off my water for the day. My tank pH has been on the high side lately (around 8.4 by lights off, and holds especially high for about hour or more after dosing my alk), and I'm trying to figure if this issue is part of the reason why.

 

Anyone have experience with this issue, or perhaps some insight into why the DI water is holding such a high pH?

 

 

Thanks for the help

[jaddc]

1. It is next to impossible to measure the pH of pure water. Your readings are most likely artifacts.

2. Your tank's pH is unlikely to be affected by top off water. Your tank is buffered against pH changes. If your tank's pH changes a lot then your problem is most likely with the tank water chemistry.

3. Why do you have to produce rodi that way? Was your DI resin depleting too fast?

 

The best way to measure the quality of rodi water is via a TDS meter.