Ive had those algae too I think, but more physical description is needed to be sure. Are your algae in mats, easily vaccuumed up as they all come up at once, or in single strands attached to surfaces but in large groups? (not easily vaccuumed)
Cyanobacteria are likely the ones in mats, hair algae/bryopsis and others are the filamentous types...even well balanced systems can have both kinds in small quantities. it is interesting to note how a shift in light spectrum and intensity (the bulb change) favored one kind over another in your system.
I think removing it by hand and keeping up your water changes will help. Eventually a steady-state (in terms of algae populations) will show for a given system, and if there is still a problem I say go for a blatant nitrogen reduction. Take out one fish or higher organism per month, one by one in order of preference, until your timely water changes and the lightened bioload have selected against the algae. Dont put them back in, the system is now tuned through bioload adjustment.
IMO, the easiest way to restrict algae in a nano is to restrict the nitrogen.
Strong skimming and/or a good refugium, low/none stocking of fish, and light feeding--algae now has a nearly impossible chance at lower-level life.
Fish require food input of various types and quantities, so the more fish you use, the more variables you will have to hunt down in order to select against a given strain of algae...once nitrogen access is no problem there is a host of built-up nutrients algae can pick from, like a salad bar for algal spores.
Fish load has great implications in sustaining algae outbreaks in our aquariums! This is all my humble wordy opinion...
Brandon
