Clearing a nasty algae filled pool

Let me start by saying, I'm a renter, with a pool, that usually doesn't have to clean the pool. My landlord is an older man who usually takes care of all the opening, closing and upkeep of the pool. This year, his health has kept him from opening it, so I took it upon myself, now I'm stressed beyond measure. We have an above ground, oval, I'm assuming about 12,000 gallon pool. Over the winter the pool was shutdown, but not covered. So as you can imagine, it was a nasty green mess. I started on June 30th shocking and doing all the necessary steps to clean the pool. While I've made a vast improvement in the color, the cloudiness doesn't want to go away. Someone please help, I'm about to give up on it. I have pics if that would help, and if I can post them somehow.