Using AC unit run-off water with low pH and TDS

[Orchid Whisperer]

Zoren:

Don't use sodium bicarbonate to adjust pH for orchids or any other plants. The sodium is bad for them, and they will die.

As Camille said, you pH measurement is possibly way off if you are using a cheap pH meter, especially if you are not calibrating it to laboratory standards. pH meters that can be calibrated properly start at $200 minimum. Again as Camille stated, better to use pH paper, which is cheap, simple, and accurate enough.

If your air conditioner water is truly at a pH of 3.3 to 3.5, the easiest way to increase the pH is to mix it with municipal tap water, which is always maintained by cities at pH above 7.0. Usually pH of 8.0 to 8.5. Cities do this to help prevent pipe corrosion.