I completely agree with ClarkiiBoi. Adding more inverts may not help your problem. I tried that quick fix with my first saltwater tank. I went with Conch, hermits, astrea, turbos, and nassurious snails. It didn't work. The algae grew too fast. I didn't know enough about algae and its causes at the time. That was my problem.
As I gained more experience and knowledge I began to attack the source... water quality. That's when I started to see dramatic improvements in my tank and not just related to algae. Good starting points are your water source & change frequency, feeding routine, and filter-media maintance.
Bottom line... cleanup crews really only attack the symptoms of the problem, not the source. It's my opinion that during an outbreak they have about the same effect (maybe even less) as scrubbing algae out by hand... it'll look nice for a bit, but it always grows right back as thick as before. At least that's been my experience.
PS - nass. snails are not really algae control critters. It's my understanding that they feed on carrion. I've watched them quite a bit in my tank and I've never seen them feeding on algae, but I have seen them go crazy over dead snails. I guess they might keep your sand mixed up with all the burrowing they do, but you'd need quite a few to make a difference during an algae outbreak.