Snail troubles and E. tenellus question

Hi folks-

Just set up a 29g "low tech" plant tank and stocked it with some plants from
Mike Trzonkowski- good plants but they came in with snails. Now I figured
having some snails in the tank might help with the algae problems but it
looks like these snails prefer my Hygro. poly and difformis :( I've been
told to get some clown loaches to help control them but I've also heard that
they sometimes chew holes into broad-leaf plants. Now I've got 2 12" paniculatus
and numerous apons I'd like to keep intact, so is this a safe introduction?
I'm thinking I might add 2 or 3 smaller clowns and remove them later on if
the snail problem is solved and the plants are ok. Any other suggestions?
BTW- I'm not sure exactly what type of snails these are, but I'd guess regular
pond snails. 

And one other question about E. tenellus- does it really require fine sand
as a substrate? My gravel is small but no where near sand-fine. Mike steered
me away from E. tenellus and instead sent me a dozen E. quadricostatus- they're
not as small as I'd hoped and they don't look all that hardy...

Thanks for any advice,

e-mail: dsung at wesleyan_edu