There is very little shade on the pool. From before 9am to past 6pm it's in full sunlight. High air temps right now are in excess of 110 degrees with a drop to 90's at night. Hence why we don't bother having a heater. Wal-mart had HTH 4 lbs jugs of 96% CYA. Pool calc said to go from 30-60 I needed 62oz. So I just went for it and dumped the whole thing. I'm not 100% positive I even had 30 ppm since the test only goes down to 30 it could be even lower? If tests out above 60 ppm tomorrow, I'll just deal with keeping slightly higher chlorine ppm. My question is this: If I lose 90-100% of 5 ppm chlorine at 30 ppm of cya. Raising CYA to 50-60 which equates to maintaining chlorine level of 8-10 ppm and I lose 50% a day (4-5 ppm loss) isn't that the same? 100% of 5ppm lost in 24 hrs vs 50% loss of 10 ppm in 24 hours is still 5 ppm per day