Maybe powdered bentonite would cling to it and drop the suspended soilfloc. It might still be in the water. Won't swell into cracks anymore but might blanket a leak. Wonder how long it will float around in the water...
I tried that method to help it sink, part A, part B, then powdered Bentonite. Then I went back over the whole area with powdered Bentonite. The part that sank appeared to have lots of clumping with the Bentonite. It seemed to help my leak for maybe a couple of weeks, and as time has passed (two years), the leak became a little worse, but has stabilized in the past year. YMMV.
