DurtBear, Now that I think about it, My old Sunpod unit had a 75w MH bulb and I believe it was a 14k (stock). I bought it used for $100. This light was better than my old PC's which came with my nano. The coral thrived much better, but the colors of my zoos were washed out for the most part. My new Current Orbit 150 MH with T5's is much brighter. Bulb is twice the size so I'm sure my old light was a 75 watt. The stock bulb on this unit was a 10k. I have heard the growth potential is greater with a 10k, but again the colors were washed out (too white). When I switched to the 14k bulb, the colors of the zoos looked much better. The best part is when the MH is tuned off and only the T5's are on. WOW !! I couldn't believe the effect !! I never knew my zoos were so colorful. I have seen pictures on the internet, but mine never looked like this until I used actinics only. I couldn't be happier with this setup. It's a little large for my tank, but it is really worth the extra $$. Seems each time I look at my tank I see new polyp growth. My leathers and turbinaria are always extended. Me and my corals are happy now.