PenguHBanswered grow question 3 years ago Ph up and down are usually not organic but do not worry, you probably only need a few drops of either one to adjust the pH to desired level.
Yes, you must measure your pH, unless your nutrients are concentrated enough to do that.
No growing medium automatically adjusts the pH or adjusts to a cetrain pH. Soil has a rather big tolerance, but if your feed pH is off, it will cause problems.
If you want to make your life easier, you could use nutrients that stabilise pH on desired levels. Advanced Nutrients make organic fertilisers that do that (and probably some other companies too) which makes growing MUCH easier, as you don't need to constantly check your pH.
One more thing, unless you buy a special product for stabilising pH during flush, you may want to keep your ph- and your pH pen, it will come in handy during the final week.