Why vaccinate adults against hepatitis B? Hepatitis B can lead to cirrhosis, liver cancer and death. Hepatitis B is incurable. Up to 1.4 million Americans have chronic HBV infection. Hepatitis B is 50 to 100 times more infectious than HIV.
Re: Pool about to overflow from heavy rain dunno of this works, but try this: put one end of a hose in the pool, the other in a lower part of the garden. Now you need to suck on the hose (the side outside the pool) untill water starts running, normaly, the water will drain.
You can swim 2 hours after adding, but if you can, allow for one full turn-over of the water. this is mainly is you're making an adjustment to the pool water. A turn-over is a full and complete filtration of all of the swimming pool water. A pool shock is a different story.