The aqualines are, by far, my favorite 10k (13k?) bulb.
But they are expensive! The cheapest I have found them was at
www.premiumaquatics.com
This time around I cheaped out and bought 10k XM's just to try them out. Much more yellow!!!!!
Next time around I'll be back to Aqualines.
But I wouldn't really say that they are "blue" at all. Maybe "white" at best.
In my experience most 10k bulbs burn a little on the yellow side.
The Aqualines are less yellow ( but I wouldn't say blue )
If you want a more blue bulb, check out the Hamilton 14k
hope that helps