I never heard of KW doing that, but I guess you learn something new everyday. If you're using the "reef aragonite" which has a larger grain size than "sugar fine" aragamax or Southdown-type sand, I bet that's part of the problem. I had some of that stuff clump up on me, and it's not good, because that part of the sand bed is not functioning. (no sand bed critters burrowing) I would suggest taking all the clumps out, replacing the sand with the smaller sized particles, and seeding from as many sources as possible. In fact, I propose we have a "live sand swap" sometime rather than, or in addition to, a frag swap. That we we'd all get better diversity in our sand beds.

As far as the hagen test kit reading, I wouldn't worry too much about it. Probably the test kit has a 40ppm margin of error anyway. If it keeps going down you'll have to figure out some more efficient way of replacing calcium.

HTH
Matt