General Care Discussion :: MVB Distance

[erinemcgreevy]

I have a mercury vapor bulb in Murphy's 125g tank. I have the light set up in a corner facing his basking dock which is about 18" away. Murphy also has a floating log which periodically floats under the bulb. He tends to bask on his log when it is there. My question is is he basking too close (the log is about 10" away from the bulb)? If he chooses to be that close to the bulb and the heat is apparently not bothering him will any harm be done?

Also, can I feed him eggplant?

[marisa]

What brand of MVB do are you using and what's the wattage? If it's a T-Rex Active UVB Heat bulb and it's 100 watts, I think the mfgr's directions say it should be a minimum of 12 inches away. If you have a Powersun, I think it should be the same, although the box you purchased it in or the directions that came with it should tell you. You could also go to the mfgr's site for the info.

I'd follow the mfgr's directions, especially if the bulb is new (and would be emitting more UVB rays than an older bulb). What's the temp of the basking area with the bulb 10" away? A good range is 88-90F. If it's significantly higher, I'd move it away, closer to the mfgr's recommendation.

I've never fed eggplant to my turtles and don't know whether it's good or not. It's good to concentrate on leafy greens, though.

[erinemcgreevy]

I have a sunforce 100 watt bulb. The manufacturer says that it should be positioned 18" away from the basking area which it is. The basing temp is 90 degrees. My concern is that he has been basking on his log instead of the platform and the log is 10" away. Should I move and anchor his log away from the light? What will happen if he suns himself too close to the bulb? Also when he is on the log he is usually not in direct line of the light.

[marisa]

OK, according to what I read about it (from Big Apple Herp---is that where you got it from?), it's supposed to be 12 inches away with a screen and 18 inches away without it; you, I assume, are not using a screen.

From what I understand, you have a basking area and a log, but your turtle is choosing to bask on the log? In your initial post, you said the log is about 10" away from the bulb, in your last post you said when your turtle is on the log he's "not usually in the direct line of the light." What type of fixture is the MVB in, a clamp lamp, with the log nearer to it than the basking area? Or, is the MVB bulb being hung from above over the basking area with the log 10" to the side of it?

Are you sure the temp of the basking area is 90F? To me, it would be difficult for a 100-watt MVB at a distance of 18 inches to heat the basking area to 90F, and if it's not, then perhaps your turtle is choosing to bask on the log, which is closer (and warmer); this assumes that the MVB is in a clamp lamp. If it's not, and if the bulb is hung over the basking area with the log 10 inches to the side and your turtle wants to bask on the log, then it sounds like the basking area is too warm.

The heat is one thing, the amount of UVB rays are another (the closer to the light, the more exposure, but you really can't tell if it's too much unless you have a UVB meter). Just curious, but why does he need a log and a basking area? If you want him to bask on the basking area, you could take away the log and move the basking area somewhat closer to the light (just check the temp). If you don't want to change anything, I'd watch your turtle very carefully for signs that he's getting too much UVB (eye or skin problems, for example).

It's a little difficult to make suggestions without knowing in what and how the MVB is positioned, and frankly, because of the brand of bulb itself. From the little bit of checking around that I did, the Sunforce does not have a very good reputation. In the future, it would be much better to buy a reputable brand that's been thoroughly tested so you know what you're getting (T-Rex Active UVBHeat, Mega-Ray, even Zoo-Med's Powersun come to mind). The Sunforce is newer (and a bit cheaper), but this is one piece of equipment you do not want to experiment with.