Just do the "deep clean" I have seen posted here. Open up the top. Gently push a garden hose into your sand and move it around to loosen it up. All the gunk will start to float out the top of the filter. Just keep doing this until the water coming out the top is pretty clean.
Some people seem to recommend doing this once a year just to flush out stuff the backwash did not get.
Some people seem to recommend doing this once a year just to flush out stuff the backwash did not get.
