algae problems

[kchamp]

I been fighting with algae for a few weeks now and it just keeps getting worse.
free chlorine 7.3ppm

I been fighting with algae for a few weeks now and it just keeps getting worse. I have shock it and shock it but no luck, the pool store told me to drain it and start over, but I said that wasn`t a good option for me, so they gave me a bottle of 32oz. algae control 60, and four gallons of liquid shock to try. I have a sand filter hayward and a 24x52 about 15000 gals.
free chlorine 7.3ppm
total chlorine 7.3ppm
combined chlorine 0.0ppm
ph7.7
hardness 210ppm
alkalinity 0ppm which I got on my test strips that this was 120ppm
cyanuric acid 90ppm
copper 0.04 ppm
iron 0.09

Edit: Merging info from two posts into one--aylad