In Therory could u use a t5 UVB grow light

[DeadFxce]

just a question I've been wondering since they are cheaper than the reptisun

 

[Kaizen]

Depends on the uvb produced. As I understand it, there is a wavelength sweet spot for d3 production...somewhere in the high 290s or low 300s. If a uvb light produces tons of uvb at 315nm, it might prove ineffective as a source of d3 producing light. I know some growers use uv light just before harvest to increase resin, but whether this lines up with the uvb required for d3 synthesis is unknown. Only way to tell is with a solar meter.