nomofatum
Well-Known Member
I run 2x 315 CMH 3100k, 1 600w HPS, and 2 100w UVB 9.9 tanning bulbs in a 4x8 space. With vs without the tanning bulbs is obvious in the results. The 315 CMH do produce some UVB, but the issue is that every layer of glass the light goes through significantly reduces the UVB. Most of the CMH bulbs are double layer bulbs or single layer bulbs with a warning to use in enclosed fixture only. Once you add the second layer of glass the UVB values drop to meaninglessly low levels. If you want UVB from a 315 CMH, get the single layer bulb and put it in an unenclosed fixture at your own risk.