Snail Problem

["Thomas Zaccone" <tomjean at worldnet_att.net>]

I have been a lurker on this board for a while and enjoyed the information
the group provided. As a novice, unfortunately, in the area of aquatic
plants, I have had little complementary information to provide.

I set up a 90 gallon tank and put a layer of organic humus beneath 2-3"  of
gravel.  Then I planted the tank with Echinodorus tenellus. E. bleheri and a
few low growing crypts.  They initially did extremely well, the tenellus
spreading throughout the foreground and the other plants filling in well
behind.

I used gravel from another tank which had Malayasian Trumpet snails.
Gradually, very gradually, these creatures bagan to exhume the humus and
deposit it in layers on top of the gravel.  This created a mess, burying the
plant stem bases and covering some of the leaves with the humus.

I dosed the tank with multiple doses of Rid-A-Snail.  This reduced the
number of the miserable creatures to a smaller level, but did not fully
exterminate them.  They have succeeded in exhuming just about about ALL of
the humus to the top of the gravel at this point or contaminating the gravel
layer with it.

Now, I feel my sole alternative to this mess is to break down the tank and
set it up again.  Since the plants did so well, I would like to use humus
again.  However, I want to make sure there are NO more of those damnable
snails left anywhere.

Is there anything I can safely use to ABSOLUTELY de-snail the plants,
gravel, and tank?  I had used a weak bath of Alum in the past on incoming
plants, but apparently these damn snails are resistant to that as they
established themselves in the tank where the gravel came from anyway,
despite the Alum.  I tried using clown loaches in the tank, but their
rooting around in the gravel made the situation worse, so I removed them.

Is organic humus the problem? Should I use organic topsoil instead?

Any suggestions would be appreciated.

Tom Zaccone