I currently have three tanks up and running. All three tank's ph is sitting between 8.0 and 8.2. My tap water however, is 7.2, even after letting it sit for up to 48 hours. There is nothing that all three tanks have in common except carbon filters and mopani wood. Two are gravel the other is Flourite Red. Two have live plants, the other does not.
Does anyone know why there is such consistency between my tanks but such a divergence from the tap water?