Cyanobacteria is a type of bacteria that can bloom, and then blankets the sand and rockwork in our tanks. It's an eyesore and people object to its presence in our systems. You have a few products to help combat it, and then there is the non-chemical approach as well (explained in the article linked below).
RedCyano Rx (by Blue Life USA) works well.
This product is designed to remove Cyanobacteria. Cyano is often referred to as red algae, but since it is actually bacteria in nature, it has to be resolved a little differently. If you prefer to avoid using a product in your tank, increase the flow in the area where cyano grows, do water changes, skim well, and double check the age of your bulbs. Over a period of weeks, it will eventually die off. Using a turkey baster, you can blow it off the rock and corals, and with flexible tubing it can be siphoned out of your tank. I have waited it out for weeks before, and it did go away.
I have used RedCyano Rx (and ChemiClean previously) many times, and never lost any livestock at all. The product is great. Mix it well in a cup of RO water, using the correct dosage for your tank, and pour it in an area of high flow. Turn off the protein skimmer for 48 hours. Within 24 hours, all cyano should be dead and gone. Its main ingredient may be erythromycin (I think), and this kills off the bacteria as promised. It is recommended to change 20% of the water after the treatment has concluded. With the skimmer being off, it might be wise to hook up an air pump and put an airstone in the display area of the tank to maintain good oxygenation. Running carbon after treating would be wise.
The only thing I want to emphasize that if you have an abundance of it present, siphon out as much as you can prior to treating the tank to reduce risk to your livestock.
Additional reading and links: