[tang daddy]

I would say you have 2 options, get something that eats it like a turbo snail or out compete it like dosing.

While you had mentioned that the urchin will knock down corals, the turbos do their fair share of bowling. Dosing will cut down nutrients but cost you some change $ and time.

I have alittle bit of an algae issue however it is kept at bay by manual removal and doesn't seem to spread worse, I do dose alittle when I remember.

I am feeding the tank quite heavy and it's running skimmerless so this may have abit to contribute to the problem but everything seems to be happy.