Mike-Your algae can be controlled with a copper based product called Cutrine. It comes in granular and liquid form. The liquid should kill both the floating and submerged algae depending on the depth of the submerged algae. If it's within 2 or 3 foot of the surface it'll die. As described on other posts here it'll most likely grow back in about 2 months. It's just the nature of the beast. How big is your pond? How much of the pond area is covered? Is there obvious nutrient rich runoff such as ag fertilizers, lawn fertilizers or livestock waste? What's the average depth of your pond? These are just a few questions you should look at before you treat your pond.