If a quantity of water has a pH of 2 like in your stomach how much more acidic is it than pool water which has a pH of 8?

The pH scale is logarithmic, so a pH of 2 is 100,000 times more acidic than a pH of 8. This means that water with a pH of 2 is significantly more acidic than water with a pH of 8, like stomach acid compared to pool water.