0ppm Nitrate

Howdy!

I have this 20-high (relatively new):

This photo is actually about a week old, so I have a bunch more growth.

The plants:
Val Spiralis (back right)
Creeping Jenny (right side)
Reiniki (back)
The three lobelia (midground)
Blyxa (left side)
Ludwigia (left midground)
"ice crystal" (left foreground)

The fish:
10 neon tetra
3 pygmy loach
2 golden honey gourami

I did a fishless cycle, and, upon its completion, my nitrate was (depending on your interpretation of my (uncalibrated) nitrate test kit, between 40ppm and maybe 80ppm.

After the cycle. once my nitrite got down to 0ppm, and I added the above fish, my nitrate was still (on my API test) pretty red, in the 40ppm range. When it got above 40ppm I did a 25% water change, and was doing them 3-4 times per week.

At the time I added the fish, I added the above plants, and yet the nitrate was still registering at 40ppm - 80ppm (once it gets above 20ppm on my API test card, it's pretty hard to tell the difference). I was still testing ammonium and nitrite as well, and once my nitrite was steady at 0ppm after introducing my fish I stopped testing nitrate every day. Imagine my shock after FIVE DAYS of not testing NO3 to discover that it had gone from 60ppm (best guess) down to ZEROppm.

Thinking this was artifact I cleaned all my test tubes and shook the HECK out of APIfreshwater aquarium test kit nitrate #2 and tested it again. AND I tested it again the next day (today). STILL ZEROppm nitrate.

SO.

Do I need to fertilize nitrate? I am planning on adding 10 neons to my school this weekend and a three-fingered-fistful of Oto to my cleanup crew. Should I let the plants fend for a week and test next weekend? I have to admit I've been feeding a bit heavy since I saw that 0ppm on the nitrate test.

At this point some of the stems are looking like they're ready for propagation, and all the plants have, if not roots, then at least new leaves growing.

Tips? Advice? Anything would be welcome!

Thanks,

Sam