Well I know that Blacklights are used on night time lizards who otherwise wouldn't get the needed UVs (I use them on my leopard geckos). I was just thinking that with a low enough wattage that the emmisions of UV
would be to low to even penetrate the water....but maybe I'm just thinking wrong. Also would a blue light be better then say a red light?!?! I notice that most people here use red lights to find things in the tank at night....oh well maybe I'll try all of the above and see which one looks best....
Also on a side note I found this intresting link about UV lighting
The last part
UVB and UVC, as well as the shortest UVA wavelengths, do not go through ordinary glass. Even Pyrex and other more ordinary forms of heat-resistant glass can be used as shields to block UVB and UVC.
Really makes me think that maybe, just maybe with a glass cover I can use a blacklight without the UVs coming through....what does everyone else think?