There are a few steps to cleaning up a green pool. All steps are equally important.
Filtration- The pool pump must run 24 hours a day until the pool is clear. When the water pressure at the returns in the pool is reduced or the pressure gauge is 10-15 psi above the normal operating pressure, the filter must be backwashed. Backwashing will unclog the filter .
Chemical- The use of chlorine and algaecide will be the best way of clearing up the pool. The more chlorine you use the faster it will clear up. You can never overshock. Sufficient Shock Must Be Administered To Ensure All Algae Spores Are Eliminated. The pool should turn white 1 hour after initial shock treatment.
Brushing and Vacuuming (Before you add any chemicals)- When the cover comes off, if the water is clear and the floor is covered with algae, vacuum the pool to waste (You will beat the whole process by days). If the water has no visibility, brush the pool as much as possible. The more algae you brush off the walls, the faster the filter will remove it from the water. When you can see the bottom, vacuum the pool to waste.
When the pool is no longer green, but cloudy- use clarifier. Once the pool is clear the water chemistry will need to be balanced with a water test at our store.