i think it`s good to mix up your ph levels when watering once and awhile, in your grow medium range. just me not sure if it matters.
i`m in hp cc coco-soil mix and so far my plants like between 6.2 and 5.8 ph,
If your water is high alkaline it will raise the ph of the medium quicker , so its better for some people to drop in the range to stop it raising as quick
reason you get hard and soft water nutrients