I'm using a multi pronged approach I take a trash pump and send the discharge to a pool about 35 feet above the pond and I take the intake with a flexible hose on it and suck up the muck off the bottom.I then let it settle and drain the clear water to my bait fish pond. I also added aeration last year. I will see how good it works.diving down I can feel holes and troughs were I pumped the water down. So it is letting some aerated water get down to the bottom at least for a short time. I can feel the softened areas when I dredge afterwards. Long slow process but I don't have to drain the pond down and kill my fish.