yes that is almost definantely BGA. Its primary cause is a low level of Nitrates in your water. The easiest way to fix this is to dose nitrogen fertilizer, generaly in the form of KNO3, a level of 10-20ppm will promote plant growth while keeping algae in check. Another avenue is to reduce other available nutrients to be in line with your Nitrate levels, the simplest of this being to reduce your photo period,how long your lights are on, and make sure you are not overfeeding your fish. All other treatments are only temporary and you will find yourself with recurring outbreaks of BGA.
physical removal: pretty self explanatory. if u dont have a gravel vac a piece of airline tubing will work, just a hellova lot slower.
Blackouts: Blackouts work because your higher order plants have reserves of energy that they can survive off of if they are unable to preform photosynthesis. The BGA as a single celled organism lacks these energy reserves and starves.
Hydrogen peroxide (H2O2): This works by oxidizing the bacterias membrane and is consumed, made inert, by the process, dont use more than about 2ml per gallon, when dosed correctly is 99.9% safe for all your inhabitants. It is best done via spot treatment, a small syringe is preferable.
Antibiotics: last ditch effort as it kills all bacteria both good and bad, can cause your tank to cycle, which is bad. Can have copper in it which will kill your inverts. Overall unhealthy for inhabitants.
