Quote Originally Posted by waterbear
To break up the clumps and flush out the sand open the filter to expose the sand and stick a garden hose in it. The sand will loosen up and the water will overflow and carry any dirt and debris.
This is a good idea. Even after having opened the filter three times already, stirred the sand by hand and done several backwashings, when I used a garden hose it stirred up a lot more 'stuff'.

It would have taken too long to let it run clear, so I put the top back on and then immediately backflushed. The water ran cloudy for much longer than it ever has before, so I guess I got most of it. The sand looked 'right' this time, so I think this beast is finally tamed.

Other than fixing this sort of problem, it seems to me that sand could not ever really 'wear out', correct?