Thinking this is some sort of Bacterial or Algae bloom but would like some opinions. Tank in a few months old and this didn’t really start until the CUC was added. I did have a snail die, ammonia spike then back to 0 nitrite 0 nitrates 7. Phos 0 salinity 1.025 temp 79.
Looks like a bacteria bloom. I suspect it will clear up by itself. If it becomes a chronic problem you might want to look into a UV sterilizer. That should correct either a bacteria or algae bloom.