this doesn't show up like the ubiquitous airborne-spore hitchhikers we are used to in other algae genera...from what I can tell it's a mad hitchhiker that comes in physically on live rock and coral frag bases. In all the pico systems Ive done where I got lazy and hair algae formed and then either killed the tank or was beaten back with good husbandry reinstatement, I've only had asparagopsis once and it was in the first reefbowl it was personally devastating. I started seeing it in my local fish store's frag tank thereafter...the only way I know to treat it is with boyds chemi clean but it still came back vengefully but maybe my dosing wasn't correct because I was having to ad lib it for a one gallon highly aged setup. I believe I've seen others do things like phosphate pads and direct removal of live rock/replacement just for more ideas
watch your iodine additions when battling red stuff of many genera (meaning lessen or stop Ia dosing) slimy and spiky as well. just found this article that confirms some of the suspicion of this growth but there appears to be good news in the battle against it:
http://www.aquatouch.com/algae.htm(edit 1/5: Saw similar pictures on marinedepot.com in Eric Borneman's forum and asked him about asparagopsis and he felt sure these were not. Having said that, the control methods linked above are what Im seeing as I look across threads on the subject fwiw)