Most of the time PH rises in soil/less. You will hear of rare occurences of having a low ph in soil. 2 things cause this, first and most importantly is the use of tap water with high amounts of sediment. It can be controlled by making sure your mixture is slightly lower than where you want it. For instance if your target is 6.5, then look for your mixture to b in the 5.8 - 6.2 range. Over time you will get build-up unless you are doing a proper, fertz, water, water. That being said all of it depends on your base soil and the fertz u r using. All vary slightly. You are organic so i'm not quite sure how it swings as i'm new to orgs!! It works the other way also, for instance if you are using R.O (reverse osmosis) water you can find that you run into a low ph in your soil due to the fertz, also if not flushed properly, based on your medium/fertz. Most chemical fertz lower ph, or any i've played with do. Key thing is to make slight adjustments and only one thing at a time, so you can find out what is creating the problem. Write it all down and your next round should b a complete success as you've found the issues and now know how to resolve them. Looks good and look forward to riding this to the finish with u. Peace!!