I have the stock light. I run it for ... I dunno, 12 - 15 hours a day, unless I remember to turn it off earlier. I only fertilize with Flourish comp (.4ml) once a week, if I remember.
I'm growing mosses, dwarf sag, some ludwigia, b. australis, hydrocotyle japan, some random dwarf floaters, and a few other things I'd have to go look up the names of. I have zero problems with growth on these low light plants, and just a little bit of algae on the glass that I don't bother with removing since the shrimplets are constantly all over it.
But I'm lazy!