All readings were in range except CH. Confused, I just put some Hardness Plus into my pool to bring the CH from 175 up. Put in about 12 lbs. This morning CH 225. checked the chlorine this morning and it was low .5-1. Used the PoolMath and put in recommended 3 qts 2 cups 8.5% liquid chlorine at 7:15am. Now at 3:00pm reading no chlorine. ????? help what happened? What do I do? Pool store says typical "Chlorine Block" put in CYA.