1. Drain the pool, and refill.
2. Read, and follow, the Super Simple Recipe: http://pool9.net/ssr/

On a 3,000 gallon soft-side pool, it's cheaper and easier to drain and refill, then it is to clean up. The pumps and filters supplied with your pool are adequate -- just barely -- to keep your pool clean. But they are too small, and the cartridges too low quality, to clean up algae in your lifetime. (Well, not lifetime -- but it can take a month, literally!).

Go heavy on the bleach while filling - there is algae residue that you must clean up, and not allow to grow. At all!