Just to clear up a little confusion, Cyanobacteria is the correct name for the algae known as "blue-green algae". It is the most common of the many species of algae growing in fresh and saltwater all over the world. Algae is definitely not seaweed, seaweed is any of the very many plants growing in saltwater. Algaes are unicellular organisms that have many, but not all the characteristics of plants. Cyanobacteria contains chlorophyll and requires sunlight to live.
http://en.m.wikipedia.org/wiki/Cyanobacteria and you can find this from many other sources.
The "algae" in diesel is commonly a fungus, sometimes a bacteria, and there is an algae that can live at the interface between fuel and the water in the bottom of the tank, though I think it is less common than the other two types of organisms.
I heartily agree with everything else in your post, and can only add that I have had success with "Startron" fuel treatment. They claim that it kills whatever is growing in your fuel, and breaks it down so small that it will go through the injectors with no problem. All I really know about it is that it seems to take a lot less secondary cleaning of the fuel system when I've used it.
Mitch
