The Change of Black Amazon Swords

>Hi Every One:
>I recently get some black amazon swords from Delaware Aquatic Imports.
>The leave of those plant are in an oval shape when I first get them. But 
>I notice the new leave have a different shape compared with the old 
>ones. Generally speaking the old leaf is round and short and the new 
>leaf is more sharp and longer. Actually it look like totaly two 
>different plants.  The growing rate of those plants is OK.  Most old 
>leave decay and new one pop up. Does that mean they need some trace 
>elements.  Here is my tank
>Size - 55 gal, 
>pH - 6.8, (automatic co2 contrl)
>Light - 140 watt ( 10 hours )
>Substrate - (DuplaRit G 500 grams, the tank just setup 2 months ago)
>Water Change - 10% every week
>Please post your comment, thank you very mush !

The swordplants you received were grown emersed (with the leaves above 
the water line).  Many aquarium plants will grow one type of leaf under
the water and another type out of the water.  Just give them a few weeks
to adjust,  and your plants should do fine.