As for me they were the lights which allowed my vallisneria to grow in my ancient 65G tank, which was rather deep 24".
Right now i use only one Grobeam 600 over my no co2 - 22G tank, 24" X 14" X 16"(high) and i am pleased with it.
I also use TMC leds over my saltwater tank, I use Aquabeams 600 Marine White over my reef tank.
Michel.