Lighting Q!

[Abraham1907]

Well I have a 10 gallon paludarium and I bought an 18" light fixture at home depot and I have a repti-glo 2.0 bulb in it. This light is supposed to help plant growth and good for reptiles and all that good stuff so I chose this one! I have two questions, fist of all is it ok to leave the plastic shield on the fixture, I wasthinking it would stop the beneficial rays from penetrating through so I took it off. Secondly, does the distance between the light and plants make a big difference, because I was thinking about attaching the fixture to the bottom of the tank I have above it so it won't look bad just sitting on top?

[Rainfrog]

Fixing it to the above tank would be fine I would think (im not the lighting or plant guy) I do know UVB wont travel through glass or plastic so I would remove your cover if you get something that need the UVB. Most of the options you listed though dont need it or can have thier Vitamin D3 needs met through supliments

[ubstrong]

distance between plant and light does make a difference. lights don't affect the plant at a distance of more that about a foot, depending on the plant, and lights get old and weak and need to be replaced at least each year. at least if they are to do any good for the plant

[Waterkeeper]

Making glass that allows UVB to pass through is more expensive than glass that does not.. so bet that it will block most of your UVB. (unless you have a hood made with starphire glass)

if your lighting fixture has a plastic pane REMOVE IT because it does limit the UVB. fluorescents start to loose measurable intensity less than 1" from the surface of the bulb, so you want the bulb surface as close to the pane of glass that It is penetrating, that way you get all of the light emission within the tank.

check this out, found it on a turtle forum.
ZOOMED Reptisun 5.0 through 6MM glass at 0 inches from tube face. Result is 10 Uwatts/CM Squared. In other words measured with glass held up to tube face. Since the Reptisun xmits 85 Uwatts/CM without the 6 mm glass, then this represents about an 88% filter capacity of the glass.

Now the Sun measured on a sunny day gives UVB readings of about 250 Uwatts/CM squared. So if you take this common glass of 6mm thickness then you should xmit 12% of the UVB or about 30 Uwatts/CM.

[jpstod]

I bet if you look at the Fixture you will see a little sticker that reads:
NOTE: Remove lens for UVA and UVB Output. If Not removed yellowing of the lens from UV exposure may occur.