Http://water.ky.gov/groundwater/Pages/GroundwaterAwareness.aspx
When a chemical reaction takes place it changes the composition of the reactants. The ways to tell if a reaction is occurring are,
1-Release of heat
2-Production of a gas
3-Formation of a precipitate
4-Change in color
<span>Based on your information 1000 times greater than pH 13 is the best I can come up </span>with.