I don't think it's splitting. I think the outbreak of dinoflagellates is irritating it. Other than siphon, water changes, GFO, reduced photo period, is there a way to wipe them out? I've changed 30% of water since last week. Tonight I siphoned what I could and cut lights to 6hrs.
One plus side to dinoflagellates is they seem to irritate or kill TX Trash Palys.