Looks like chara to me, too.
Jacklegg, have you pulled any & smelled it? If smells strongly of sulfur/garlic, almost certainly chara. I have a variant in my BOW.
Only solace I can give you is that fish seem to like chara. If you have to have a plant, there are much worse things. I know grass carp eat it.
7 acre pond in east Texas, full pool reached March 2016. CNBG, RES, FHM stocked Nov 15; TP May 16; LSL bass 30 June 16. Added 100 12 inch N LMB and 1,000 shiners Oct 17, 150# TP and 70 HSB May 18