Ive looked at a few things people have been saying and its all going over my head,everyone is using abraviations,and i just dont now what there talking about.If i check my pools chlorine levels in the morning and there fine,then when we use it in the afternoon,then check it again after and it reads no chlorine is that because it needs more salt or is that normal,the acid demand test is all good and so is the total akalinity,its a concrete pool salt chloriated and god only nows the rest please help,ppppllleeeaaassseee