Sandbed cleaning concerns.

[Aquattro]

I only occasionally stir my sand and let the flow carry it to the sock. I might change out a portion of it after a while, but dirty sand doesn't concern me much in the short term (year or so). My 180 was a beautiful setup, but when I tore it down, the sand was disgusting. This tells me that it can manage itself, acting like a sink for some period of time. I do think replacing every now and then is good, just not sure the time between now and then..