You can also hasten the precipitation of the clay by dumping gypsum (I like the decorator rock whic h is about 1.5" in diameter) in the inflow channel of the silt catch basin. As you probably know, the calcium in the gypsum binds with the negatively charged clay particles, neutralizing them so they don't repel each other and will settle to the bottom.This works best on the smallest particles, which are also the slowest to settle out.

Layton Runkle