400 W Metal Halide Bulb E40

[kajaksurfa]

Hello,

I am looking for a 400 W Metal Halide Bulb (bulb fixture E40) to my 100 gallon plant aquarium.

I have tried some different bulbs and found them to give very different color rendition.

For example some bulbs gives a yellow hue (the cheap ones for driveways etc) or very greenish hue (6500K) , others a very bluish (>14000K).

One day I found one used lamp in a flea market for almost no money at all, and it gave
a fantastic natural light to plants and fishes (never seen anything like it compared with flourecent or other types of lighting) it was just like the light I see when I go diving in crystal clear springs ....unfortunately there was no text on the bulb so I dont know any data on it.
Now the bulb is burnt out and will not ignite any more.....so time to change.....

When holding a white paper over the aquarium I noted the hue to be very white,light blue with a slight purplish cast (kind of similar to the color from a grolux) to it and this is what I am looking for.

What bulbs are the public aquariums using?, I know most are using MH but from what make?.

If you have tried some differnt Metal Halide bulbs I would love to hear about your experiences........

Thanks Leif