There is only one macro that I would EVER consider
purposefully introducing into my SPS display. Chaeto. All of the other macro algaes will establish themselves in your tank, and then when you are having a rough month or two for maintenance, they will explode and take over the tank. Caulerpa holdfasts are IMPOSSIBLE to remove from live rock (as are gracilleria holdfasts) Each one is a growback point for the algae and they make thousands of them. Macro belongs in the refuge unless you want algae as a main feature for your tank. (I have a display that does)
Grazers: IME Each grazing fish is as individual as a child as far as the kind of algae it will eat. My Scribbled Rabbit fish will not touch anything except the prepared algaes.
My Kole tang eats almost anything green, but will not touch Valonia or any red algaes. So buying a herbivorous fish to control algae is hit or miss.
Chaeto is a ball algae. It clings to its purchase point by tangling strands around it and it is trivial to remove. It is ever so slightly more demanding than the caulperas (I have had a softwall sized piece melt into nothing before) but works great in most people's systems.
Gracilleria has another annoying habit. Its strands are individually very fragile, so when you harvest a handful, you will invariably create several dozen little frags that float everywhere and will travel through your circulation into the main tank, no matter what you do. This is great if you have a fish that will eat it, but I don't and now I am always weeding out little colonies of it in the main display. And making more little frags.... etc.
All macro algaes (IMHO) love flow. Mine are always colonizing the screens of my powerheads and overflows and clogging them up. They grow like crazy on them. I have to take a toothbrush to my overflow screens and powerheads monthly now to remove the gracilleria and restore flow through them.
Don't get me wrong, I love my macros. Just don't introduce them into a system and expect them not to do what they do best. Colonize and grow.
Sorry for the book, but this is a favorite topic for me
I think I'll do a blog article on my Macro experiences since I appear to be in the mood to write
BTW if anyone has a tang that will (proven) eat red gracilleria, and wants to fatten it up, please let me know. I can't add a sailfin or a foxface because of the kole and the rabbit, but any other suggestions are welcome.