I think systems like that will work because they drain to waste. When i was using it top feed and the nutes didn't get recycled, the pH of my run off was fine.Love my pH-perfect Sensi coco nutrients. I haven't measured pH or ppm in years, just 2ml A & B per liter and no problems.
When I moved to a system where the same water in the rez interacts with plant roots multiple times it no longer worked.
I have seen some other growers have success with it in recirc systems, but I personally could not recommend it in that scenario as the pH readings got higher and higher in a short amount of time.
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