Thanks for the link, PoolDoc. I poked around at the SGM website and found their warranty details. #2 on the list of limitations reads, "Some loss of aggregate is expected, especially in a new installation: This is not to be considered a failure."

How much constitutes "some loss of aggregate"? Who knows? But the very, very little aggregate I've lost so far would seem to me to fall way, way below the threshold.

So I won't sweat it any longer. ;-)