HookedonSalt
Your question may have opened the Pandora's Box on debate. Perhaps more consequential than who is prettier? Mary Ann or Ginger?
Back in the day There were three common MH Bulbs... The 65K Bulbs which were way yellow but had a very nice 450nm spike for about $65. These were commonly used to grow "tomatos" in ones basement and a favorite of reefers on a budget:sad:.
The other two MH Bulbs available were the Ushio and Radium but were well over $100 each.
At this time I've seen outstanding LPS tanks lit with only 110 watt VHO 420nm, but personally could only afford the Iwasiki 65K. Growth was great but looks were simply OK. Even tried blue glass but that got too hot and cracked...(Note this was still when one could find Meat Loaf on 8 track)...
Sanjay has done some excellent work listing the spectrum of these bulbs and without has the most qualified opinion on the best schedule.
This is only my experience...
The deeper you dive the more blue you have. Past 30 meters the reds, greens and yellows are gone. The Zooanthellea algae in the corals have adapted to receive the blue or 420-470nm
Here is a spectrum chart for the most common Chlorophyll A&B
I have found the 450nm the sweet spot in growth. This is your Royal Blue XT-E
The Cree Cool White has a serious 450nm spike which is why its good for growth as well.
Overall its your choice on looks or what light makes your corals look prettier (Ginger v Mary Ann) but growth is the 420-470 or simply the 450-460nm Cree Royal Blue.
Bill
