Did you ever figure this out? I have the same exact issue. Installed a new Reverse Osmosis System connected to the kitchen sink. PPM is 11. PH I set to 6.0-6.5. Running the grow just like I have for years, but now using this Sink RO system, when I water the plants start dying. WTF ?
Plant Photosynthesis = Light + Water + C02
Ask yourself, what happens when you deprive a plant of Light or Water, in any condition?
Then ask yourself what happens when you deprive the plant of C02.
Hate to reign on feelings and hunches, but running C02 to the end IMO is a key part of the...