Before you jump to any conclusions: I've been BBB for years. I got algae after days of heavy pollen rains one week ago. Since then, I have been constantly testing my water, keeping the FC level at mustard algae numbers, using skimmer socks, brushing the pool, vacuuming out pollen after it settles, and skimming out everything that falls in. It is still green in the deep end. Pollen is still collecting in the vinyl wrinkles, although it is much less (I had big puddles of it). I need the pool to be swim-ready in 24 hours for a pool party (invitations sent before the pollen rain.)
By keeping FC at mustard algae levels, I mean keeping it at or above the number on the Pool Calculator recommended for my pool, based on my CYA levels. That is 19. I have been testing it in the morning, and it's still above the mustard algae level overnight, so yes, I've been doing it right. I just doubled-down on my 12.5% liquid shock this morning, but it doesn't seem to be having enough effect.
I have been through this other springs, when we got lots of rain for many days in a row. The root of the problem is the pollen, which falls into the pool like someone is dumping buckets of dust into it. If you visualize someone dumping two buckets of yellow pollen into your pool, that is what I'm dealing with here. The pollen gets mixed into the water, algae starts to grow immediately, and unfortunately getting it out is super-hard. It won't go where I want it to go -- down the floor drains or into the skimmer, to be caught in the socks. I don't have an auto vacuum that can stay on 24/7 and clean it up, so it stays suspended in the water. And that is why I'm considering flocculent.
I am probably going to add the flocculent. I can't find anything in here about using it without wrecking your chemistry -- just lots of people saying "don't." Yes, I am desperate, because my only other option is to cancel the party.