What is THE bluest 400w MH bulb on a M59?

[Ralph ATL]

I need to know the bluest 400 watt bulb that will run on a Hamilton M59 Ballast. I am currently running 2 Hamilton 20k bulbs, but I would like a little more blue in color. Since this is over a 90 gallon, par is not a factor.

I cannot run Radiums!

Thanks!

XM?
Helios?
what?

[grigsy]

Try the XM 20K. I have used it and it is a fairly deep blue and a good choice for an M59 ballast.

[Ralph ATL]

Thanks!