Skimming = nutrient removal

Ineffective skimming = high nutrients

High Nutrients = Nuisance algae growth

Therefore, Ineffective Skimming = Nuisance Algae Growth

The math is pretty simple.

There are also a couple of other things here. Cyano likes low Redox. By fully oxygenating more water, you are increasing the redox. Also, you may not have had enough flow going through the becketts to be pulling an adequate amount of air. I'll let matt or someone that is more knowledgeable about becketts to jump in there. It seems to me that if you have a dual beckett that means you are splitting the flow through both and only gettting half the flow rate. It would seem that you would need to have twice the flow of a single beckett to draw the same amount of air. If you flow rate was the same as a single beckett, then you be cancelling out the benefit of having a double.

On the flip side, doubling the flow means decreasing the retention time in half. As long as this is taken account in the design of the skimmer you should be fine. In other words, you have double the capacity of the skimmer over that of a single beckett.

Matt, please jump in here.