+1 20k xm SE 400w...u can see what it look like when u come over my place moto..i already have my cube running/cycling right now...i also have t5's for actinic lighting...
just the 20k xm is blue,i love the look of it..u will see it when u come over
Helios 20k (very undependable) followed by radium 20k. Then XM 20k, reeflux 20k coralvue 20k, and then reeflux 12s from bluest to whitest and in order of favorite.
Im currently running the reeflux 20Ks. I like things blue if you cant tell.
FWIW, the ballast driving the bulb has a huge effect on the color of it. I run icecap electronic ballasts
This is good because I know almost where to send you because I asked the same question before I bought my bulbs.
Sure it a 250W but you can see put any two bulbs side by side. The Radium look great but when you put them next to the XM bulbs you will see the XM bulbs are actually deeper blue.
Also depending on how big or should I say how deep your tank is you might want to think about going lower wattage. My Zoas grow best under a compact believe it or not. They do not need a ton of light.
I used nothing but XM20k for the last two years (400w SE variety) and liked them a lot. On my new system I decided to try the Reeflux 20k in the 400w and 250w flavor (SE bulbs, two of each over an 8' tank). The Reeflux bulbs have a much more noticeable actinic effect on my ballasts (250w Icecap e-ballasts and a magnetic dual-output 400w Hamilton ballast). So far I like the Reeflux a lot more, but I'll have to give them time to burn in. If you've been to Barrier Reef, their main display tank and frag tank are lit by the Reeflux 20k bulbs.
Salty, not to pick a fight, but, if you dont have direct experience with 400's you will never know the color differences between the two. 250's and 400's have totally different colors despite being the same brand and kelvin on the same brand of ballast. For example, I love the color of the 250 reeflux 12k SE on an icecap ballast, its a very nice deep blue. I dislike the 400 reeflux 12K SE on an icecap. Its a very crisp white. YOu cant refer someone asking about 400s to a web site showing 250s. IMO it just doesnt work for a color comparison.
Sometimes the color / intensity are very similar as well however. My 250w Reeflux 20k bulbs are almost identical to the eye as the 400w Reeflux 20k bulbs sitting right next to them. I've got the 250w pair on Icecap ballasts on the outside of the 8' tank while the 400w pair is on a Hamilton magnetic ballast covering the middle portion of the tank. There's no noticeable color difference between the two wattage pairs on the tank but whether that is because of the ballasts or the bulbs just being designed to be nearly identical is hard to tell.