Hi
@Tillbert_1899 these ground-based PH readers I think are not very reliable, at least with me, I already used one. analog and then a digital and both were always on 7-7.5 even with all the water set at 6 PH. I did several tests with them on the solutions to set the PH and continued at 7-7.5 .I stopped using. I use a pen to read the water, setting all the watering to PH 6 will leave your substrate at 6. good luck 👍