I think we all are on the same page in this discussion. The most important factor in my opinion is to know your lake environment and identify your largest problem. We use pesticides as per the label instructions, and sparingly only when necessary to keep our lakes and landscape in acceptable condition for our selected purpose. There are many very good comments in this thread with excellent ideas. Controlling unwanted pests (weeds) in an aquatic environment where few can be tolerated is a complex task. Needing a broad reaching program. Many factors exist such as water chemistry, nutrient load in the water, level of tolerance to some or no weeds, geographic location of the lake and so on. My approach to our lakes (in the SW) is based on these factors. Summarized: We have an aquatic pest control consultant that tests the water chemistry and nutrient load yearly and we have established a data set. Weeds and algae will only thrive where the conditions allow, sun light and nutrients are required. Reducing both will help but is not all that is required. Grass carp, if allowed, work very well in controlling emerged weeds. Other fish such as Tilapia work well in controlling algae for us. If necessary, we use Chelated copper to control algae, such as Golden algae. This is not done unless the population of the target pest exceeds tolerable levels. Any aquatic herbicide is applied by a licensed aquatic pest control company. We have only had to use these services two times in the past 20 years. By monitoring and reacting appropriately to our condition, not hesitating to properly handle and apply algicides and herbicides, we have been successful in providing a great skiing environment. Geographic location of the lake will vary the necessary programs greatly. A lake in the south east is a very different animal that one in the Arizona desert.
Anyway, sorry for the long rant. Cheers and Happy New Year.