I went to brush my pool last night. I notice stuff on the floor but also some on the sides of my steps and walls. I ran my hand over it. It came right off didn’t feel gritty or slimy. I adjust FC to 8 each night. CYA of 50. Yesterday was cloudy so FC was 6.5. Added some LC according to pool math would bring it to 9. Added a little extra since I was brushing. Brushed the whole pool. Waited about an hour tested again got FC 8.5 CC 0.5. Tested again this morning got FC 9 CC 0.5. Knowing the test has about 10% error I would say those results are the same. I always thought the only thing on vertical walls was algae but it didn’t eat any chlorine. Anybody have any thoughts am I missing something.