Lakes or ponds are wonderful to have. The dogs love to swim in it and you can fish in it with the kids. Aside from that, it makes a wonderful addition to the property and gives a cool feel to the land that you have. Put a fountain in the middle of it to improve aeration and water circulation. This, in and of itself, is a great way to maintain the balance between algae and other plant life.
When this balance is thrown off for whatever reason, the result is an overgrowth of one or the other and sometimes both. Normally, there are checks and balances in an ecosystem and these keep anything in the pond or lake from overgrowth or undergrowth. If this balance remains, you don’t notice any problems because there are likely none at the time.
Usually, the aquatic environment will take care of itself if it was started properly. Along with aquatic weed control, the other species of different plants and other creatures in the pond will help determine how weeds will be controlled overall. For example, some species of fish do eat certain weeds and algae. These fish could be useful for preventing such overgrowth.
Otherwise, if you do have one of these bodies of water and the weed growth has gotten out of control, understand that this can affect all of the life in the pond. The worst result could be the death of everything except for the weed in question.
Instead of ending up with the worst case scenario, please do yourself and the water life a favor and seek professional help. Find a good service in your area for controlling the weeds and algae in your pond or lake. They will come out and find many ways to reverse the situation to normal once again.