Equipment Review and Discussion :: 160 watt MVB?

[octpusgirl8]

I'm going to be needing a new MVB in a couple of months, and i was wondering if a 160 watt flood would be too much. I have a 100 watt T-rex flood now, and at 12" away from the basking area it's only about 85-88 degrees. That's measuring the temp with a black probed thermometer, which i've heard can cause a higher reading. Turtley basks okay, but i know from his pre MVB dyas that he basks more when it's a little warmer. I also worry about having the bulb down so low, i don't want to splash water on it accidentally or cause eye irritation for my little buddy. I hang my lighting fixture from the ceiling, so i would be able to adjust it easily to get it to the right temp. It could be as high as 4 feet from the basking area if need be. Any opinions? I know i could just boost the basking temp with an incandecsent bulb, but that would defeat the purpose of having a MVB in the first place. It's not a pressing concern as i'm not going to be buying one for a couple of months, just wanted to throw it out there and see what everybody thinks.

[steve]

I have one in my dry dock area and it's about 3 feet away from the where they would bask. I haven't measured the temps, but it's not dramatically warm at that distance. It's been performing fine so far but I don't have it on everyday, so I haven't been measuring the output.

[marisa]

Because they give off quite a bit more heat than the 100-watt ones, 160-watt MVBs are good in rooms where the temp is quite cool and/or if the tank as a very large surface area (how big is the tank/container?). I'm using two of them, one in a basement, where the ambient air temp is quite cool (60-64F). In both case they're the recomended distance (about 18 inches from the basking area).

To me, the main purpose of using a MVB light is for the UVB rays as well as the heat, and if you're going to have the light really far from the basking area, it would not justify using it (the UVB rays are substantially diminished).

Just to see, have you tried a regular thermometer and compared it with the probed one? If as, you say, your turtle is basking OK I'm not sure I'd go with a stronger MVB. Is the one you're currently using in a reflective dome?

[octpusgirl8]

I have a 75 gallon tank, and the bulb is in a white dome, since i heard bad things about putting UVB lamps in a shiny dome. The only other thermometer i have is a meat themometer and it reads about 81 degrees. Turtley basks a couple of hours most mornings, but when it was hotter he'd bask a lot longer. I wasn't anticipating needing it to be more than 18-24" away, i wouldn't think the UVB output would diminish that quickly. The UK lighting survey only measured the 100 watt bulbs, i checked there for a comparison.

[SpotsMama]

I'm surprised your basking temp is so low. I use a 100 watt T Rex flood in a fixture with no dome, positioned about 14" from the turtle and the temp stays in the low 90's. Spot loves it and probably basks 8 hours a day. I wonder why the big difference?

Perhaps you have a lot of air circulation that dissipates the heat rapidly, or perhaps your basking platform is closer to the rim of the tank, which would also allow more heat to dissipate. My basking platform is probably 8" below the rim of the tank, and I've got a home made cover with some deer net resting on the rim that's 2" or 3" tall, all of which serves to retain a lot of heat in the tank.

[octpusgirl8]

I think that's the case, the basking area is about 6" from the rim of the tank, there's no cover, and my house is fairly drafty. I might look into some sheets of plexiglass to cover part of the tank with.

[marisa]

My MVBs (both 100-watt and 160-watt) are all in reflective domes (shiny interiors) and I've never had a problem using them. If there is a lot of air circulation, perhaps a 160-watt would do. My point was that if a 160-watt MVB were used but placed a much greater distance than the mfgr considered to be optimal, the strength of the UVB rays would be much less, and this would defeat the use of the bulb as it was intended.

[octpusgirl8]

They say that they project useful UVB up to 6 feet so i would think at 2 feet it would be fine. In any case, i've got a while to think about it.

[marisa]

Yes, you do. And the bulbs do project UVB rays up to a certain distance. And the 2 feet you mentioned is better than the 4-foot distance you mentioned in your original post.

[steve]

Hey octpusgirl8, I just measured my T-Rex 160 watt flood... the room temp is 68F and the warmest part of the basking area is 85F. The closest distance between the bulb and the basking is 20" (18" is the minimum recommended on the box and I'm not sure why I thought mine was 3 feet before). The bulb is also projecting 50uW/cm² of UVB at that area.

[octpusgirl8]

Thanks Steve That's extremely helpful, i think i will be getting the 160 watt when i get a new bulb.