I just bought a foreclosed home with an in-ground fiberglass pool. It has not been cared for at leaste 2 years. Filled with algae (dark green), water bugs, and a few dead rodents. I just pumped out the pool to about 5-6" deep and added a little shock and removed what rodents i have found. It has a sand filter but I have not done anything with it except to see if it is getting power (it is) and it appears to pump as well. I have never owned or maintained a pool. I guess where do I start? How do I clear out the algae from the pool and the system?