I am posting for a friend who doesn't have access to the forum. Here are her test results:

19000 gallon above ground Doughboy oval pool
Sand filter
CYA 151
FC 5.5
pH 7.7
Total alkalinity 111
Adj. Total Alkalinity 66

I have converted her to the BBB method, but she is struggling with clearing the pool of algae. Last week her CYA was over 300, so she drained about 1/3 of the water and was able to get the CYA down to the measure above.

Other than keeping her chlorine levels high, what do you recommend?