Acid Rain is considered acidic when it has a pH less than 5.6.
Erupting volcanoes release gases, particularly sulfur dioxide -SO2. In a series of reactions in the atmosphere, the SO2 combines with water molecules, forming a dilute sulfuric acid that returns to the earth as acid rain. Kilauea volcano releases 350 metric tons per day of SO2 during eruptive pauses, and 1850 metric tons per day during active eruption.
Acid rain caught in catchment systems does not have the opportunity to benefit from the earth’s natural buffers. Acid rain increases leaching of metals including lead and other system materials into the water. Water in catchment tanks in Hawai‘i that are downwind of the volcanic plume have often had pH readings as low as 4.
Raise pH levels in your tank by adding baking soda (sodium bicarbonate). Which you’ll add each time the tank replenishes itself.
Uncle Tilo’s Acid Rain Mineral Pack with granulated calcite (also known as calcium carbonate) and Corosex (also known as magnesium) will provide slow continuous release of minerals into the tank.
During an active flow we recommend to also add in baking soda for added measure.