Well, I did a little 150w mh comparing, lately..
Looking at which mh was the most blue and of the three I have looked at, it's almost a 3 way tie. I've looked at the xm 20k, the Radium blue and the Giesemann megachrome blue. They are almost identical to one another..
If I had to choose, I'd say the giesemann bulb is the most blue, but only by a slight margin. looking right at the glass of the bulb as it is lit, can you see a slight difference, looking at the tank under the bulbs it would be almost impossible to notice a difference..
Unfortunately, I don't have a par meter so I can't measure that..
I'm not going to spend any more money on bulbs, so I will go with what I have.. Probably the giesemanns.. Good German made bulb.. Never had a faulty one..
As for t5, I will probably run 4 gieseman actinic plus or Ati blue plus.. As far as I'm concerned, they are identical. And them one pure actinic..
I've ordered the Faune Marin royal blue ultra, just to see what they look like.. Don't know much about them..
Tonight I will test ammonia, nitrite and nitrate to see how the tank is progressing.. It's still cloudy but the snails I have added are cleaning the tank like crazy right now.. Even the 2 blue t5s that I am running are causing a small amount of algae to grow..