We double shocked our pool last week (I believe it was last Monday) and had FC counts in the teens for days. The past weekend our pool was still too high to swim in. PH 7.8 and alkalinity 110. We noticed green still accumulating at the bottom of the pool and thought dead algae. But now that our pool is finally close to swimable FC level the bottom is completely covered again. If we vacuum the pool looks immaculate. What do we need to do.