Whenever I vacuum my pool within a few days I see what appears to be a handful of algae spots show up in areas such as next to wrinkles in the liner or seams. They are a yellowish / green in color. Some vacuum up like "dust", others need 1 light scrub with the vacuum head to remove them. The spots take several days to come back and always in the same spots. Once they are back, they don't appear to "grow" in size.
Test numbers have been:
CC 0 - .5
Temp 68 - 72
To maintain my FC, I am currently running my filter 4 hours a day with my SWG set at 36%.
The water was crystal clear when I removed the cover. I scrubbed and vacuumed the pool and added enough granular chlorine to bring the FC level up to 31 which took many days to drop to "normal levels".
Question, if this is algae I really don't want to slam the pool, once I get into the pool would rubbing a chlorine puck on it over several days kill it?