Actually the first link was talking about a 20k and 8k bulb.
This is still irrelevant in reference to T5HO's and MH
considering she is stating on using MH
with the combination of T5's. She doesnt dipict wheater what kind of fixture and how many only that lighting consists of 1 MH
250 ushio and 1 39w 20k and 1 39w 8k. If your going to make 2 T5's compare to 1 MH
then thats not even a close comparison.
I think the depth of a tank is definitely relevant, unless you want to put all your high light corals in the top 30%. MH will penetrate deeper just because it is a single point light source and everything is more focused.
Im sorry but i would have to disagree and let me explain. The first part is talking about depth of tank, well depth will matter and the water is the factor of that, not the lighting or lumen output. I know what your trying to argue but its still not relevant. Lets think about the sun for a minute for me to better explain. We all know the sun is the most abuntant and powerful light source their will ever be.
So lets think, we have the sun millions of miles away. Is it more a MH
or a T5HO, i know what your thinking its a MH
because of the single point of light. 8O Oh im digging myself in the hole now
but wait its not a MH
its more like a T5 because of the fact is
#1 the distance
#2 and it covers millions of square miles of ocean light is distributed evenly acrossed.
Heres another thought:
I have not seen any photometric reports on a MH
for aquarium fixture use from my work or never have seen it on the net.
but what i have gotten is:
400 watt MH
puts out 26,200 lumens.
6 bulb 54watt T5HO puts out 30,390 lumens