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mercury vapor bulb--is it safe?

PostPosted: Fri Aug 21, 2009 12:55 pm
by mark king
Hi everyone--I have a baby RES that we got about a month ago, and I've been trying to get him all set up with the right equipment (boy what a shock that was after letting my little girl get him at the beach on impulse!). Anyway, I've adjusted to the responsibility and he's a cute little guy.

I'm concerned about the MVB I bought. I read that they were the best for UVB, so I bought one. But it is SO bright that, even trying to avoid looking at it, just the stray rays that catch my eyes leave them feeling slightly burned. Why wouldn't this be doing the same thing to the turtle's eyes? Anyone heard of that being a danger? Also, my tank is only a 20L, and it appears these are meant for larger tanks. I have a 125W Hagen Solar Glo which I bought at reptilesupply.com. As long as I have it far enough above the tank that the basking temperate isn't too high, is that OK?

Thanks for the help!

PostPosted: Fri Aug 21, 2009 1:05 pm
by papoopeepoo
Welcome!

Be very careful with MVBs if you have a tank under 55gallons. The heat from the bulb can make your water temps very dynamic and hard to control. I would suggest waiting to use that bulb until you have a larger setup. Until then you can use a coil flourescent UVB bulb and an incandescent bulb for heat (75watt works for many people here). You'll need two seperate bulbs for UVB and heat, and therefore you'll need two fixtures. Until you get a tank 75g+ that will work just fine. Make sure both bulbs are over the basking area, and temps are in the 90-95 degreeF range to entice basking.

I have an MVB on my 6 foot tank, and on hot summer days like this it needs to get turned off for half the day because it heats up my 120gallons pretty quickly.

Good luck and have fun!

PostPosted: Fri Aug 21, 2009 2:50 pm
by marisa
MVBs are best used in tanks that are at least 50 gallons or slightly smaller if there's a lot of surface area. 20 liters is about 10 gallons? I wouldn't use the bulb until I got a bigger tank (it won't go bad if it's not being used)---your tank is just too small for it. A conventional UVB light along with a heat source would be better for now.

PostPosted: Fri Aug 21, 2009 2:51 pm
by adam85491
I think 20L means 20 Gallon Long tank.

But yeah, either way it is too small for an MVB.

PostPosted: Fri Aug 21, 2009 3:16 pm
by mikee
adam-91 While inspecting your mvb check the uvb output. It should not be over the .50 rating. The 10 is too strong. It will damage the eyes of your turtle. Good Luck! m.

PostPosted: Fri Aug 21, 2009 3:22 pm
by adam85491
I use a 5.0 Reptiglo by Exo Terra bulb (a few years ago I think I was the only one using this, it seems to be more popular now). I don't know why people use Reptisun bulbs or MVBs because they are so expensive.

PostPosted: Fri Aug 21, 2009 3:25 pm
by marisa
I use mainly MVBs, but when I use regular UVB lights, I use Reptisun tubes (pretty much the 10.0 without any problems). They are more expensive, but the effect that they have on my turts justifies the expense (because my turts are worth it :D).

The Reptisun tubes have a reputation that the Repti-glo just doesn't have, at least not yet.

PostPosted: Fri Aug 21, 2009 3:28 pm
by adam85491
I don't exactly see the different effect between the two brands. Exo Terra is a very reputable brand and makes quality products. I don't have a hood, so I'd have to use the compact either way. Please explain how ReptiSun is better just because you pay more. If there is something to back it, of course I'd be willing to spend the extra money for it, but so far, I haven't found it.

Regarding the compacts, the Exo Terra also seems to fit better in clamp lamps as it is shorter.

PostPosted: Fri Aug 21, 2009 3:36 pm
by marisa
I'm not saying that the Reptisun (and I'm talking the tubes, not the CFs) is better because it's more expensive. Depending on the product, something that's less expensive can be as good as (or even better) than the more costly version.

To me, the Reptisun tube is better because it's been around for a while, has a very good reputation with some turtlekeepers I trust (not just because a fair number members on this forum use it) and the tube seems to agree with the turtles I've had who have basked under it. (I don't have a hood for the tank I use tubes with either.)

Not all MVBs are created equal either, btw.

PostPosted: Fri Aug 21, 2009 3:40 pm
by adam85491
I didn't mean to sound defensive, but it seemed like you either implied I don't care about my turtles because I use the cheaper bulb, or that a bulb is better because it costs more. As long as we cleared things up....

And if you don't have a hood, how do you use the tube bulbs? Just curious.

PostPosted: Fri Aug 21, 2009 4:04 pm
by marisa
Ah, I perhaps should have mentioned in my last post that the comment about my turts being worth it was a take-off on that L'Oreal commercial---you know, when whoever is hawking the hair coloring looks into the camera and says "Because I'm worth it..." That's why the smiley is there.

I wasn't implying anything about the bulb you're using. You asked, and I told you as best I could, why I prefer the bulbs I do.

As for the Reptisun tubes, I have the 18-inch ones. I use them in an aquarium fixture that isn't connected to any hood, so they can be placed pretty much anywhere. If I laid the fixture across the top of the tank (the last tank tubes were used in was a 20G long) they'd jut out the sides. So, I found something that I could rest the fixture on that would keep it pretty much over the basking area and more in the tank. I happened to find an old metal boot holder (if you don't know what this is, it's basically a stand that you would put knee-length boots in upside down to keep them straight). It's a little taller than the tank and straddles it perfectly. The fixture just sits on top of that. I have a heat light fixture with a long, bendable neck and I position that so it hits the basking area as well.

I don't expect anyone to run out and get one of these holders (I don't even know if they still make them, at least in metal), but it is good sometimes to think "outside the box." Objects can have unexpected uses. :D Other members, I think, have found that out as well.

PostPosted: Fri Aug 21, 2009 4:24 pm
by adam85491
I have no idea what commercial you're referencing lol, sorry.

I'm not saying the ReptiSun isn't a good bulb, and appreciate your reasoning. Interesting way to use the tubes as well.