Someone on here posted a thread saying legos attracted coralline better. I thought it would be a noble expiriment. So far nothing. Those threads are non photosynthetic gorgonians.
Why would lego do that? And why did you have to build something with the lego for it to do that? As it has evolved for millions of years in a natural reef enviroment, why would it be attracted to lego. Don't take this the wrong way but that is quite odd.
First legos are made out of ABC plastic which is high in carbon therefore may be attractive to organic carbon based lifeforms. Second of all I built a castle cause I figured the predators would love it. Third of all they did. Forth of all I take nothing personally.
I would just take the lego out mate, it will grow in time. As long as you have sufficient calcium levels. Then again it all comes down to personal taste.