I added some macros to my HOB refugium about a month ago. One of the racemosas went sexual right away and I pulled it all out. The other had some die off and since has grown several long branches but not grape bubbles. The mexicana has remained about the same since I put it in. I've been dosing iodine and iron and the tanks has a nitrate level of 20 - thats why I went to all of this expense! All of the caulerpas came in attached to rocks. Shouldn't they spread to the mud substrate? I have pulled out some of the mexicana in hopes that it would stimulate some growth. Can anybody think of anything else that might help spur this stuff on?