Aeration through blower has many features: It can mix the water from the bottom of the pond, with the aerating plate or pipe fixing at the bottom of the pond. It has a greater efficiency, and much energy saving. What's more, it is much easier for maintenace, because the blower is fixed in the blower room, and there are only some plate and pipes under water. If there needs some actions, much convinient to change some accessories of blower.
But for aeration through other machinery, it only can mixing the water surface. And if there's something wrong with the machinery, it is much complicated for maintenace. Because large part of the machinery is under the water surface.
What's more, blower fits for the needs of large pond, and aeration machinery fits for small pond.