FC too high?

[jblizzle]

Have you deep cleaned the sand filter?
I would do that and then try a little DE in the filter. Sand filters can be slow clearing up the last bit of cloudiness, assuming you are passing the other 2 criteria to end a SLAM.

 

[pooldv]

Please add your pool info to your signature as shown here, Pool School - Getting Started

Main drains are normally opened/closed by a valve at the equipment pad. My pool has a 3way valve that controls the flow between skimmers and drain. It can be all skimmer, all drain or a blend.

Here is how to clean a sand filter, there is a link it to a deep cleaning tutorial also
Pool School - Maintenance and Cleaning of Pool Filters

Here is how to Pool School - Add DE to a Sand Filter, many people find adding DE speeds the final clearing of the pool.