Depending on the situation I have used the following as an emergency method to reduce planktonic algae that was to dense.

Take a 5 gal bucket and put a hand full (estimate 4-6 ozs) of CUSO4 in the bucket add 3 gal of water and stir until dissolved. This produces blue water. Take a hand sprayer (3 gal) and add the blue water 1/8 and clean water 7/8 to fill. Spray from boat lightly over about 15% of the surface area in parts. For example small areas of about 3% in 5 different areas leaving untreated areas in-between. It has when used reduced my plankton densities by about 40% on a temporary basis. It does carry a high risk and you have the potential for CU accumulation in the system (bottom muds).

This is my last ditch emergency plankton reduction method. I am not sure what the effect of doing this with aeration ongoing would be.