My first thought when seeing that image is Dinoflagellates. It can looks like dripping snot with a bubble at the end. I know that sounds gross but that's the best way to describe it. In a few days or weeks it goes away, when the biofiltration recovers from the die off of some kind of organism. Was there a recent death in the tank?
I believe Cyano and dinoflagellates can exist together, but then it may be the Cyano that Holyzion identified. In either case, an outbreak of algae is usually brought on by extra nutrients. Even the unseen death of a bacteria population can bring on an algae bloom.
Has the tank overheated recently?
How are the Alk and Ca levels?
May we see a pic of the entire tank?
A new light can create changes. Light acclimation is critical. That leads to my second thought which is, What's up with that acro? It looks bleached, or is that it's natural color? Was the tank acclimated to the new light by starting at low power/intensity and raising it slowly over 2-4 weeks?
Hopefully these questions will help. Also look in the Reefkeeping Tips for the discussion about eliminating Cyanobacteria/Slime Algae.
Aloha