Help! Pool was Green most of summer!

This was the 2nd season where the my pool (24'x15'x52" AG) started out clear, then by early July it turned green.

I chlorinate with 12.5% sodium hypochlorite, adjust pH with muriatic acid, and adjust alkalinity with baking soda. I check paramaters with a Taylor test kit at least daily.

Parameters usually fall in the range of:

FC: (I shocked all the time. Usually 10-20 ppm)
pH 7.2-7.6
Alk: 80-100

The one thing I noticed when I took the cover off the pool this season, was my CYA was zero. The highest it reached this season was 30.

I was in a constant cycle all summer where the pool would turn green, then I would shock to 20ppm. About a week later, the green would go away but still remain cloudy. It would be fine for about 2 weeks, then turn green again.

Could my pool be victim to the soil bacteria that I've read about in this forum? If so, should I go ahead and drain the pool and start over again? I've spent alot of money on chlorine, electricity running the pump 24/7, and algecide (poly quat 60).

please help!

When you shocked the pool, how long did you sustain the shock level? Were you brushing it daily? When you let the chlorine level come back down, what was your maintenance (daily) chlorine level? If you didn't keep it at shock level long enough to kill all the algae, especially if you let the chlorine level dip too low when it came down, then it's likely that you've had the same algae bloom all summer. You have to keep it high enough and long enough to kill it all before you're going to be able to get rid of it. Also keep in mind that polyquat depletes your chlorine level, so anytime you use it, you have to go back afterward and raise the chlorine level back up.

Janet