The goal is to have pool water clear enough to dye test 4-5 vertical cracks in the top 24" of the pool. I've drained the Present water level down 30".

Right now the water is somewhat green - I'd say a mild case, but upon filling up the pool, adding to what's in there now, I don;t think I'll be able to see through the water well enough to do the dye tests.

So, if I could find a way to shock the water in the pool now, and get it mostly clear - then my hope was to have clear enough water, upon filling, to do the dye tests.

If dead algae does drop to the bottom, if left alone, I don't know. That's where I thought the Flock might help. However, if the water is likely to still be murky then I still won't be able to see through it.