If you are fertilizing your lawn at the lake this year, or hiring it done professionally, please make sure the fertilizer is phosphorus-free. Some of the professional companies will comply with this request, some do not. Also, do not over fertilize! All fertilizers and nutrients contribute to algae growth—phosphorus is just the worst. On your bag of fertilizer are three numbers, usually separated by dashes (for example 20-10-15). You want that middle number to be zero, that is the phosphorus number. Preventing phosphorus from entering the lake is the best way to control algae growth.