I don't know exactly what kind of snails I have, but I have alot of them. I Think right now I have about 60 snails in there, many of them getting pretty big as they grow. I also have alot of hermits, scarlets and the little blues. Occasionally I also find baby snails in there, both the type that have the snails the small blue hermits normally come with and some other various creamier colored snails. The rest of the cleaning guys are 2 cleaner shrimp and a peppermint and a sally light foot crab and Marvin the pathetic brittle star.
This is in a 90 gallon tank with a 29 gal sump. I don't know if this all is 'book' right and occasionally I have to throw in a few more of something or another when it looks a little low, but its done alot of good.
While I don't think my tank is photogenic enough to post brag pics of how its doing, its not horrible looking, and I haven't had the energy for six months to do any cleaning at all of it. Sure there is some algea on the glass and it has snail marks where they've been eating it diligently, and there is a little hair algea and some various, man I should get up and clean it, but it is more than good enough and the cleaning guys are going more than good enough of a job that I can not worry about it and promise to clean it -after- the baby gets here in February. I've seen dirtier tanks by far in fish stores where they have people clean them everyday.
Seriously my clean up crew is like having a tank maid and I am greatful I got them every day. And yes, I occasionally lose a snail to a hermit attack but I also occaisonally lose a hermit to the hawk fish. I just pick up more of each about over 2-3 months, or just one or the other, its a good excuse to drive to the fish store

But the slow attrition of cleaners is hardly noticable. I do find the blue hermits less snail agressive than the reds, the blue's seem more content to pick up the misc shells that came in the arognite sand stuff.
Rachel