[Aquaman]

Just for the general information, alum, or aluminum sulfate can be very effective on colloidal clay suspensions. Colloidal clays are, if I remember correctly, same charge particles that repel each other, thus keeping them in suspension. They are also tiny particle size so their weight does little for settling. Alum causes the particles to "floc" or coalesce, making them heavy enough to drop out of suspension. Alum also bonds with phosphorous, creating aluminum phosphate, that makes the phosphorous no longer available for plant uptake, thereby reducing overall plant biomass within your system.

Aluminum is generally inexpensive, as far as pond chemicals go, but has to be monitored upon application to make sure that the water doesn't acidify to the point of being harmful to fish or invertebrate populations.