Hi Pal, if you imagine you have two plants, one is located in the sunlight, the other plant is located in the shadows.
Our Damsels need a certain Level of light, intensity, correct light spectrum etc.
The 30W light does not have enough Power to get a nice harvest. Of course it will grow, but quality will be poor. Hope this helps a bit. If you have further questions, throw me a PM. Cheerz, OimRausch