I just put one in soil and I Just added ph down from my local hydro store til I got to 6.5. It's in tge ground so I can't test what it's at the bottom like you can with a pot. Iv read you can flush your soil or medium with super low phd water to lower the ph of the medium itself. That way it won't raise the ph of the water you add later so much. No personal experience on that tip though.
Thanks for the kind words. Mines neat because I didn't build it, lol. It guys like sauce that do super low budget DIY that are really the most fun to watch. That and the guys with super big amazing grows. The two extremes.