General Care Discussion :: Redundant lighting? can there be too much UV exposure?

[dhtang]

Hi, I've been doing the following setup for the past 2 years. I'm recently being told that I'm using too many bulbs/tubes for lighting. Can anyone confirm this?

Lighting setup:
Repti glo 5.0 13W 18" tube
Repti glo 5.0 26W bulb
Repti glo 2.0 15W 18" tube
Sun glo 75W spot lamp

Are the first two Repti glo products essentially the same? my greater concern is can there be too much UV exposure from this setup? Any comment is appreciated.

[dhtang]

forgot to mention the cycles:
all lighting are timed to go on at 7am to 7pm.

[marisa]

Not with the UVB strengths you've got. The sun gives out many times more UVB rays; 5.0's aren't that strong and the 2.0 itself gives out a negligible amount.

But why do you have so many? If you have them over the water, your turtle doesn't really benefit...

[dhtang]

Not with the UVB strengths you've got. The sun gives out many times more UVB rays; 5.0's aren't that strong and the 2.0 itself gives out a negligible amount.

But why do you have so many? If you have them over the water, your turtle doesn't really benefit...

The main reason is because the 5.0 18" fixture was built near the center of the tank slightly closer to the basking area. The 18" tube does not cover the other side of the aquarium and I'm really concerned that the UVB rays would not penetrate the basking area (made with plexi-glass). Therefore, I have the 5.0 bulb angled on the other side to shed light into other parts of the tank. The 2.0 is just to provide full spectrum light, it was recommended. As to the spot lamp, it's the main source of basking heat and UVA.

Question: I know water does scatter UV to some extent but it definitely still penetrates, or are you telling me the rays from these artificial UV bulbs/tubes does not benefit the turtle unless he is above water level??

[marisa]

Enlighten me here----there are 2 eighteen-inch fixtures, neither of which is over the basking area at all. One is "close" and the other is there to basically light up the tank on the other side. The 2.0 is there just for "full spectrum light." You said that the basking area is made of plexiglass, but are concerned that the UVB rays won't penetrate it...

If your turtle basks on a plexiglass basking area, there should be no concern about UVB rays penetrating it---unless you have plexiglass covering the light, creating a barrier between the rays and the turtle. If so, then take off the plexiglass covering.

For maximum benefit, the UVB light should be as much over the basking area as possible, next to the heat source. (UVB lights, btw, also give off UVA rays.) So, yes, I'm saying that your turtle needs to be above water, i.e., basking, to get any real benefit from a UVB light. Can you move the basking area to be more under the nearest UVB light with the heat source next to it?

From what you wrote (and from what I understand), the 2.0 isn't needed and the 5.0's are being wasted. The UVB rays from the sun will penetrate water several inches, but UVB rays from a 5.0 light won't.

And I should ask---how big is your tank?

[Turtle Mummy 101]

dhtang: I think you have too much lighting in all the wrong places. The "wattage" isn't strong enough to harm your turtles but in order to actually benefit them it should be over the basking area. More light isn't necessairly better - it's just a waste. I can't even imagine how high your electricity bill must be

[dhtang]

My tank is a 48" 55G tank. Yea I'm using the two 18" tubing is because I used to have a smaller tank.

Thanks for clearing things up for me, I got most of my questions answered. So honestly, do you think the 2.0 is worth it at all or is it negligible?

I think I am either going to A) unscrew and reposition the fixtures so that it is completely over the basking area, OR I'll just buy 48" 5.0 from now on.

Hmm, the reason why I chose plexiglass to build the basking area is partly because I wanted some sort of UV/light rays to go through; so that even if my turtle is underneath the rather spacious basking area, he'll still benefit. But if the UV won't penetrate the water, it doesn't do much good.

Enlighten me here----there are 2 eighteen-inch fixtures, neither of which is over the basking area at all. One is "close" and the other is there to basically light up the tank on the other side. The 2.0 is there just for "full spectrum light." You said that the basking area is made of plexiglass, but are concerned that the UVB rays won't penetrate it...

If your turtle basks on a plexiglass basking area, there should be no concern about UVB rays penetrating it---unless you have plexiglass covering the light, creating a barrier between the rays and the turtle. If so, then take off the plexiglass covering.

For maximum benefit, the UVB light should be as much over the basking area as possible, next to the heat source. (UVB lights, btw, also give off UVA rays.) So, yes, I'm saying that your turtle needs to be above water, i.e., basking, to get any real benefit from a UVB light. Can you move the basking area to be more under the nearest UVB light with the heat source next to it?

From what you wrote (and from what I understand), the 2.0 isn't needed and the 5.0's are being wasted. The UVB rays from the sun will penetrate water several inches, but UVB rays from a 5.0 light won't.

And I should ask---how big is your tank?

[marisa]

Forget the 2.0. Forget worrying about whether or not your turtle is getting any UVB rays under the basking area. You want your turtle out of the water, drying off and basking under a UVB light and heat source.

For now, I'd reposition what I've got. But in the future, rather than get a 48" fixture and another flourescent, I'd spring for a lamp stand (or make something, since you seem to the handy), a reflective dome fixture (like from Lowes or Home Depot) and a mercury vapor bulb. Your 55G is big enough, and your turtle will really appreciate it.

[dhtang]

Forget the 2.0. Forget worrying about whether or not your turtle is getting any UVB rays under the basking area. You want your turtle out of the water, drying off and basking under a UVB light and heat source.

For now, I'd reposition what I've got. But in the future, rather than get a 48" fixture and another flourescent, I'd spring for a lamp stand (or make something, since you seem to the handy), a reflective dome fixture (like from Lowes or Home Depot) and a mercury vapor bulb. Your 55G is big enough, and your turtle will really appreciate it.

thank you kindly for your input and recommendations!