Just to reiterate, to make sure you didn't miss it--with a CYA of 55, you need to keep a minimum of 5 ppm chlorine in your water at all times. Anna gave you some basic doseages and the results, so you need to test the water daily, and add whatever amount of bleach you need to get back up over 5 ppm. (I would dose it to about 8 ppm in the evening just to give you some wiggle room).

Janet