Yesterday @ 5:00 pm my husband cleaned the light niches: One niche and light fixture perfectly clean. The other had a very small amount of brown stuff in niche and on fixture- wiped w/ a white cloth, let everything soak for 20 minutes before my husband had to leave town. I then scrubbed the skimmers again. Don't know if it's important but for first time ever I noticed a thin ring of solid black at the very top of the water line in both skimmers. It looks and feels like black grease, but wiped off w/ chlorine and cloth. hope this does something…anything else to clean or check?

overnight numbers:
last night - tested @10:00pm FC=33 CC=3
this morning - tested @7:00 FC=33 CC=3