Ok..I don't know if you tried to attach pics to this post or not, but the formatting on it is way off. If it's brown stringy stuff it's probably just excrement. If it's tons of small bubble like stuff, then it's more likely spawning.
Yeah definitely crap. My red brain will spit out a huge string of brown crud and the first time I saw it I was kinda freaked out because there was so much but its just your coral taking a dump.