Nice tank.. However, it isn't really "super low-tech" with 2.4w of T-5.
Well it's super-low tech because of 6 months in between water changes and no ferts at all. When I started it up it wasn't supposed to be low tech; it was a normal tank. But with a full time job and a college load, I couldn't keep up with the maintenance.
I have a Marineland 160 canister (again, not really low-tech) with over 3/4 of it devoted to biological filtration. Add a huge Java Moss carpet as a nutrient sponge and voila! Like I said, after 6 months of close to zero maintenance, I tested my water and nitrates were only at 10. This was with a brand new test kit, but I still didn't really trust it, so I brought it to my LFS, where I also work. The reading was exactly the same.
I only feed my fish every other day or so, but I have never had any bouts with any kind of deficiency in my plants. I figured my swordplants would be the first to tell me if there was a problem of some kind, but they grow like mad with lots of color. I figure the potting soil underneath gives off plenty of nutrients for any plant.