This sounds totally logical and I would probably agree with you on this had I not run in to the issues I've had this season that directly related to PH. The water at my tap comes out at the high 8's (8.98 when i tested it today) and I was watering my plants with it for almost the entire season this year. I couldn't figure out what was wrong i was doing everything i've always done and they just wouldn't take off. Then they started yellowing, it almost looked like nute burn but was just a little bit different so i brought it in to my local hydro store and he told me its a PH issue. My plants aren't able to feed on the nutrients because the PH of something, most likely the water, is off, is what he told me. So i listened. I bought a cheap GH PH kit and started adjusting the PH for my waterings. After about a week i could see a significant change in my plants. By the next week they were no longer yellowing, leaves stopped dying, and they started to get their deep green colors back. Now at the end of the season I have some decent sized buds with a beautiful mix of light and dark greens, trichome production is off the charts, and literally the only thing that i changed was i started to adjust the PH of the water they were drinking. I also stopped watering from the hose and started to fill my bucket straight from the tap or at the faucet.