Aeration in some instances has been reported to reduce internal nutrient recycling enough that sometimes it can help minimize some algae problems. Certinally aeration is one tool to try and use in managing ezxcessive nutrients. Source of nutrients is a big factor in the the whole problem plant picture. However aeration can only reduce nutrients (usu phosphorus recycling) a measured amount. If your pond has more phosphorus than the aeration can suppress then there is still excess amounts or concentrations available for plant growth depending on the type of plants and their needs / requirements.
The amount of phosphorus reduction by aeration is directly related to the amount of Fe (iron) that is contain in the sediments. Soluble iron (ferrous) combines with P to form the insoluble (ferric phosphate). Aeration also plays a physical role in algal composition by altering water currents, temperature, etc.... Diffused aeration has been shown to increase phytoplanktonic algae by recycling large amounts of sapropelic sediments into the water column, thereby increasing the overall nutrient level in the upper layers (epilimnion/metalimnion) of the lake or pond. This increase in phytoplanktonic algae naturally reduces transparency which in turn controls many forms of filamentous algae through light limitation.
There has been some interesting studies done in adding iron to lakes in ponds for phosphorus "control". Of course, the addition of aluminum sulfate to lake and pond sediments has been shown to be effective in "controlling" phosphorus even in reducing environments such as in the lower water layer (hypolimnion) of lakes and deeper ponds.
In summary, there are a wide variety of techniques to control algae. Nutrient limitation is always the most effective but not always possible or practical.
http://www.thewaterplanetcompany.com/docs/10pdf/Phosphorus%20Chemistry.pdfhttp://www.elmhurst.edu/~chm/vchembook/308phosphorus.html
