Algae eating snails?

I need some suggestions on snails that will eat algae of my glass. Please if you have any suggestions, post them! : )

 

saltwater I assume
Astra Tecta snails do a good job on my tank walls
Turbo snails are another species that like tank walls IME

Steve

 

Yea, its a 30 gallon salt water starting-to-become-a-reef. How many do you have in your tank?

 

Evan I have about 20 something Astras in my 5 ft tank and at any given time I can find at least half a dozen on various areas of the glass but I still need to use my magnet a couple of times a week

Steve

 

Trochus and cerith snails for me, I have a couple turbos as well but probably won't use them in the future because they can get too big.