You can then subtract the free chlorine measurement from total chlorine to confirm the level of combined chlorine (total chlorine – free Chlorine = combined chlorine). How to Test Pool Water for ...

A Times analysis shows that increasingly complex oil and gas wells now require astonishing volumes of water to fracture the bedrock and release fossil fuels, threatening America’s fragile aquifers.

U.S. oil producers are grappling with geological limits to production growth as the country's top oilfield ages and produces more water and gas and less oil - and may be nearing peak output.