Crypt problems

Hello all,
  I am having some problems with one of my tanks and hope someone can 
help.  I have a 20g tank with 4 clown loaches and various plants.  I am 
changing to crypts which are a more familiar plant to the loaches than 
the val. and hygro I have had in there.  Currently I have planted in the 
tank two A. crispus (hybrids, possibly), rotala macrandra, C. wendtii, C. 
cordata, and a big clump of green hygro.  I have two 15w bulbs over the 
tank, a gro-lux and a cool white.  I am not particularly happy with this 
lighting, but the hygro and A. crispus are doing fine, as is the Rotala.  
The crypts, however, are not growing very well at all.  The crypts melted 
when I first got them, which didn't bother me too much.  They are very 
slow coming back, however.  

I think nothing can be too wrong since the hygro, Aponogeten, and rotala 
are doing OK.  Are the crypts being outcompeted by the faster growing 
plants?  How long does the melting act last?  I could just be overreacting.

Tank info
-20g high
-30w fl. lighting gro-lux+cool white
-hardness negligible coming out of the tap, supplemented to ~40ppm with 
     baking soda
-pH ~6.5
-temp 78deg
-nitrates ~50ppm, I'm going to step up my water changes to drop this some
-fertilizer I use alternately Seachem Flourish, Tetra Flora Pride, and 
     Coralife plant food according to manufacturer's directions
-substrate gravel with duplarit K
-undergravel filter

Thanks in advance for any help.

PS.  I recently bought a crypt, about 6-8 inches high, leaves green on 
top and red on the bottom.  The leaves are about 50% stem and are kind of 
slender.  This is a C. affinis and not a C. wendtii, as the store had it 
advertised, correct?