CO2 carbon dioxide October 13, 2017 by Pahlen AB CO2 pH regulation for the pool CO2 is a dependable and easy to use system for pH reduction in the pool. pH-MiniDos Pahlén pH-MiniDos is stable and easy to use for stabilizing the pH value with CO2 (carbon dioxide). pH-MaxiDos pH-MaxiDos is a dependable and easy to use for pH stabilization in the pool. For use in public facilities.