UV tube height

[heidi250273]

So Shelvy's new enclosure is just about finished and looks amazing but I was wondering what the height of the UV tube should be from the top of the substrate? The heat bulb is around 12 inches from the top of the substrate. We haven't put Shelvy in his new home as I want to get the temperatures just right first. When he has moved in and got settled I'll post some pictures

 

[Tom]

What type of UV tube? The best method for this is to use a light meter.