looks like snail shells to me
snail shells aside, i agree with tropicalnorth...
Looks like standard run of the mill green dust algae, no idea what it is technically. I also don't think you can get rid of it completely (stop it growing back that is), there seems to be some on every tanks glass. An algae magnet keeps it in check though.
There'll always be some algae growth. Get some snails of the genus Turbo and they'll take care of it for you. In a properly balanced tank (snails to algae) you'll rarely have to clean the glass.
ight man thanks for the info.... i need to get a new cleaning crew... im going tio get some sinls that go under the sand