Do high water temperatures cause chlorine to be used up quicker? My inground has been rather stable this year, but lately the chlorine has dipped rather low. With our auto safety cover on all the time, the SWG was only on 20% and it maintained the chlorine level around 6 without any problems. Lately, the chlorine level has been declining with each test (every few days). Yesterday evening it dipped to it's lowest of 2. I added about 80 oz of 6% bleach and turned the SWG up to 75% and let it run all night. This morning I tested and it was up to 3. With my CYA level, I like it to be around 5, so I'll be adding more bleach today to get it back up, but is it the heat that's causing this? The water has been around 91-93 degrees for the last two weeks which is really when it started the steady decline. I typically run the pump for 9 hours with the SWG at 20% and that was plenty. As I said it ran 9 hours yesterday and then I turned it back on last night at 11pm when I added the bleach and ran these tests this morning at 6:30.
pH: 7.2 (just recently dipped from 7.4 - I'll bring that back up later today also)
Note: Our auto cover is closed unless we are in it, so it doesn't get much full sun.