Water Balancers: To keep your water in balance, you should test the pool several times per week for chlorine and pH levels, and adjust as needed. Test total alkalinity every few weeks or if you have pH troubles, and test calcium hardness and cyanuric acid levels every month. pH Increaser: Granular Soda Ash.
The alveoli are surrounded by tiny blood vessels, called capillaries. The alveoli and capillaries both have very thin walls, which allow the oxygen to pass from the alveoli to the blood. The capillaries then connect to larger blood vessels, called veins, which bring the oxygenated blood from the lungs to the heart.
Your alveoli are surrounded by minute blood vessels, as this is where gases diffuse from your lungs into your blood and from your blood into your lungs. Oxygen passes from your alveoli into your blood and carbon dioxide, which is produced when your cells break down nutrients, passes from your blood into your alveoli.