Hi,well i never measure ph of my soil grows,. only if i have any problems with the girls. Soil is able to regulate(buffer) the Ph by itself. And i never had problems. Just 1 time when i try to regulate the Ph in my soil ( my first indoor grow) it ended in a total mess. Since that day i know plants are ok in my Soilmix. I only measured the Soilmix before uisng it. with a soil measure kit