I had similiar problem a month or so ago. I bought some Phosfloc but did not use it after asking around. I spent more money, but less hassle, on 3 (3 liter) bottles of PhosFree over a 3-4 week period. I would put in a bottle (20,000 gallon pool) and backwash appropriately (generally after about 4-5 days). I ran the pump for at least 12 hours a day. It took time, but it worked. So, the PhosFree stuff works. It will make your pool a little milky for a day or two but that clears up. Good luck...I feel your pain.

Mike