I am actually doing that with my current pair of female gold dust day geckos. I had originally taken the advise of Leann and Greg Christensen (www.daygecko.com) when I got my first day gecko about 12 years ago. At that time I was new to planted vivs and didn't want to have to worry about changing out the florescent tube every 6 months (they had gone to great lengths in their book to recommend a specific type of light that would show the gecko's colors the best and I didn't want to have to try to find one every 6 months). I did keep that day gecko for 11 years. Now I have other reptiles that need UVB so I have a regular 6 month light change and the new day geckos are included.

Aliza