Out of my tap ph is 7.4. After aging for 24 hrs. - 3 days still 7.4, maybe 7.3, hardly any change. If I was to change about 50% from the tap it would still have micro bubbles. This is the reason I age my water. When doing extra large WC's on planted tanks you can really see how many micro bubbles/false pearling there is. Our source is lake water, ph 5-6.2 depending on the time of year. They use sodium hydroxide to increase ph to hinder pipe erosion. And a coagulant Aluminum sulphate to clot the organic matter. The low ph in our lakes is caused by many years of coal burning and acid rain. They are slowly coming back but climate change has slowed this process down some again.