New 30g tank suggestions with crypts and clown loaches

I am setting up a 30g tank for my clown loaches, which are getting
territorial, and need a bigger playpen.  I have somewhat unsuccessfully
been growing several varieties of crypt in the 20gallon tank in which they
now reside.  The plants are hanging on, but not really flourishing.  I am
planning to set up the new tank with one, or possibly two, 20w fl bulbs
over the tank.  We'll see how this goes, but more lighting isn't really in
the cards.

I really am soliciting suggestions for the substrate for this tank.  I am
planning to run one undergravel filter plate at one end of the tank.  I
have the filter stuff and don't have money for alternate filtration.  So,
one foot at the end of the tank will have an UGF plate under it.  The
remainder of the 3' long tank will be substrate on glass.  For substrate,
I am planning to have a two layer system, including a lower, richer
stratum, and an overlying poor stratum of sand or pea gravel.

This system works aesthetically, because many of the "richening" additives
aren't so nice to look at.  Also, vacuuming the gravel works ok, if I
don't go too deep.  I have had good success with and understratum of
gravel mixed with laterite in a 45g tank with South American plants and
high light, so I am somewhat optimistic that this can also be made to work
with crypts.  What should I use for the understratum for the new tank?  I
have several ideas
- laterite-enriched gravel
- laterite- and peat-enriched gravel
- potting soil
Since the overstratum will be uniform throughout the tank, which is, after
all, for display, I can use one or more of these choices in the tank.

This is also a good opportunity to do a little experimentation.  If, for
example, I used a gravel/potting soil mixture for the understratum over
the UGF plate and for half of the remaining tank footprint, and a
laterite/peat/gravel mixture over the remainder of the tank, I would be
able to compare substrate types and evaluate use of the UGF.

Anyway, I would appreciate any suggestions.


 Work Phone: (206)-543-1075             Physical Mail: Box 352700
 Fax:        (206)-543-1543                            University of Washington
                                                       Seattle, WA