Carpet plants for medium lit tank

if it helps for comparison:

i have the hagen CO2 (the pretty DIY, ha)

36 watts of T-5 over my 20 long (which has aproximately 17-18 gallons of water in it)

i dose flora pride every few days- root tabs for the plants that need more nutrients from the substrate
 
according to the updated wpg rule--you're lighting is actually high. so i don't know if the microswords would do well in my tank which is medium low light.
 
MARSILEA CRENATA (four leaf clover)
This plant will carpet out,but it will loose its flour leaves and give u just 1 spoon shaped leaf.
Spreads just like glosso,but works with lower lighting
 
I had glossostigma in my 75 with 4 40W flourescent bulbs. It seemed to do ok, started to spread and look better for a couple months, but I neglected the tank for a while last year and the quality got bad and algea really created havok. The glosso perished as did some other plants. I might try it again sometime now that I have higher light and better maintanence.

BTW the LFS here has a big display tank with some huge anubias... probably a couple plants 2 foot long or more. The main root rhizome or whatever its called is bigger around than my thumb.
 
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