I'm using soilfloc also. My pond goes down approximately same rate at 1/2 full as it does now nearly full.. At least I believe that to be true. I don't have an accurate measure when it got down below half. My thinking is I want to treat the lower basin only which will be much easier with the pond low. Either I'm waiting for it to drop or I'll be pumping it out before I apply. Hydraulic pressure might work better but less water means I can concentrate the material where I need it. Only problem I have is good ole mother nature is all I get to fill it back up.