Last night at 9 pm I brought my chlorine to an 8.5 and did an overnight test. At 6 am this morning I was at an 8. So I should be fine but tonight at 7 pm I tested and dropped to a 2. Mind you it was 115° today. Is this pretty normal to lose that much throughout the day or should I look at underline problem? I have had no problems until last couple of days.