I had 1200 watts of MH
in a open topped hood hung 12" above the water. In the summer we have an average house temperature of 77deg (I am too cheap to run the airconditioner colder). My water temperature was almost always 83 deg or better even with fans. Worse, it would go down 4-5 degrees at night. My big Iwaki pumps add a degree on their own. As I wanted a stable temperature of 78 degree, I had to chill 5 degrees or more of the water and that costs money. My experience was the MH
were like the old space heaters with the big quartz light bulb in the front. MH
did grow coral splendidly, but the rest of the overhead was not suitable for me. I would rather limit my coral collection to those specimens that thrive under LED
rather than have a coral garden I can't afford to maintain.
As a diver of many years, I am very sad to see the destruction of the reefs as well. But I can use my memory and photographs of reefs of the past to construct what I hope is a more natural reef suitable for fish and coral. I would rather have a few large spectacular corals I grew from frags, rather than the variety we see in these display tanks, where constant pruning is needed...but that's just me. Maybe too much work for my inherent laziness as well. My buddy says "that's why they make wall paper in every color of the rainbow."