Here is what Ben suggested to another poster a little earlier this season.

PAC (polyaluminum floc)
GLB Pool & Spa Products 71408 1-Quart Drop n' Vac Pool Water Clarifier (http://www.amazon.com/exec/obidos/AS...T6TY/poolbooks) @ Amazon -OR-
Blue Wave Super Floc 4 x 1 qt. @ Amazon (http://www.amazon.com/exec/obidos/AS...QTT0/poolbooks) - 4 days to ship -OR- Proteam Superfloc Clarifier (if it's available locally)