So I'm getting ready to do alum treatment this week on my newer ⅕ acre pond (two years old, stocked with LMB, BG, HBG, RES, CC fingerlings and a single koi in april), the fish are doing great with high daily feeding activity. Was just treated with soilfloc a week a ago to stop a seep in the spillway. The pond itself was built by damming off a pair semi-ephimeral steams where they converged with 15ish acre forest/brush/ and cattle pasture watershed feeding it . I've pulled 2 common snappers out of it already and know there is at least one more in there but its sub three inches and thus can escape the turtle trap I bought. After a heavy rain event it goes full chocolate milk then takes a week to settle back to the control jar level of turbidity (12-18 inches). Anyway I pulled the water for the initial test last night, added the 1tbls, 2 tbls, ect and this morning I find the test jugs, are crystal clear but instead of sinking, the floc floated to the surface. Can say that was completely unexpected. The only thing I can figure is maybe the normal concentration of 25lb/acre foot is too high, or is this an interaction with the soilfloc and I should wait longer? Sorry about the pics, I had to crop them down to get under the size limit.
Algae definitely will pick up the floc and float it about when exposed to sun and creates bubbles. There are likely other micro organisms that have ballast bubbles that get caught up in the floc as well and can lift it. Then there is always the possibility of adding salts that causes gasses to come out of solution, or even react with things in the water column creating gasses that would get trapped in the floc and lift it. In any case, it should settle once it is dark or the gasses dissolve back into solution.
