Try taking a sample of your water to the LFS
and have them test the alk
if you don't have them already. Might be be a chemical problem. If the tank was filled with dry sand, this can take time to clear until the bacteria are established. The light weight silty material can easily be suspended in the water until it gains some weight. If that's the case you have nothing to worry about, it just needs more time. The filter pad in the HOB
may simpley not be large enough (or clogged) to deal with it.
Is it as cloudy as from the 25th and how much shrimp did you add to the tank? Tank size?