Best way to rid LR of Grape Caulerpa

[Barb]

I'm thinking about getting some tuxedo urchins.

 

[veralteaquatics]

Urchins are a good place to start and long spines seems to be the bigest consumers. Instead of killing the rock, try an overnight outside in water when it's really cold, followed by an hour or so out of water; sometimes this will shock the algae enough to kill it. Also bubble type algaes seem to grow better under used or old supers actinics, so if you have old lamps try some to ones to aid the process.. Best of luck