It's an Echinodoras sp., commonly called a sword plant. Hard to say what type it is though, but most of them get very large. You gave the WPG, but not the sizes of the tanks. Put it in whichever tank is biggest, should do ok under either light level. They also appreciate root tabs and slightly deeper substrate.
I think it is emersed E. martii - the ruffled sword. Note the wavy margin + esp. the pseudopenninervature, ie. the side veins starting off round the middle of the leaf. E. martii gets about 20 '' high. Could be a Melon, too, not Amazon, imo.
Thanks Jen. Fresh, you might find this amusing;
while you graciously gave me a Micranthemum umbrosum stem,
the Bacopa monnieri was actually a hitchhiker buried in the
Elatine triandra you sold me. a week after planting your ET
one lonely stem started growing vertical instead of Horizontal,
and with extra care I nursed it into that lovely bunch of BM
you see today what I love most about BM is how it does
not seem to attract diatoms on it's lower leaves like MU does.
BM is so soft that my fish seem to like swimming thru it, but
it does not break apart into floaters as many fine plants will.
I like this BM much more than Hemianthus micranthemoides.
amazing what hitchhikers you can get plant trading.
recently I traded for a baseball of Glossostigma elatinoides.
I isolated the plants in a container for a few weeks,
(I'm paranoid about getting other peoples algae) and found;
even live Daphnia!