Here's what I have found  once I calibrate it dfwi. Using an assumed pH CONSITANT throughout the grow is really what the plant wants. Also we know if the pH is within a certain range consumption by the plant is improved. Not that you can't grow at pH7 its that from experience they do better in a certain range.

And that's all there is to it for me. Seriously I only check my pH when I start a different nutrient system. I know what amount to add for my CalMg and Si. They seem to be the foundation in the gh series(for coco)  pH. And it reliably works for the plants. So really do what works if you don't pH your system and you grow consistently nice plants, means your lucky and benefit from a really nice water source. I don't have the luxury.  Our water is hard and at pH 7+ cant count on it. My little Ro system does enough to it to make it good to use for my girls.

Everyone does it differently, the goal is the same, flowers.