Nice pic, thanks for sharing.
It is nice to start with super low EC/PPM and a near neutral pH as you would with R/O water or distilled water. Water with 0.0 EC/PPM will pretty much always have a pH of 7.0 as it has absolutely nothing in it to make it acidic nor alkali.
However, if you think about it, what is important is what is going to be present at the roots, that is where it counts. When you add nutrients to water you are going to be adding the nutrients that can be acidic or alkali in the nutrients nature. Nitrogen can add acidity to your water as in nitric acid, as can sulfur as sulfuric acid. Calcium can add alkalinity to your water as in calcium carbonate. Many nutrient mixes will move your water’s pH on their own towards about a 6.0 - 6.5 as they are formulated to do so, but they are usually manufactured to be used with very pure water and are assuming the pH will hold after it has been mixed. On the other hand if you have hard water with a high starting pH above 8, there is no telling what will happen after the chemicals in the nutrient mix react with the chemicals and minerals in your water. Adjusting pH before adding your nutrients is just adding more chemicals to your starting water that will further react with the nutrients after you add them.
It is probably best to mix in your nutrients, give it a really good stir and then maybe give it 5 to maybe even up to 15 minutes to see how after everything has interacted with everything else, what your pH ends up. You may not have to add nearly as much pH adjusters to get it where you want it. And then you will know exactly what pH you are sending to your roots.