Habitat - Indoor :: Single Bulb Setup with measurements

[slider_keeper]

100w ZooMed PowerSun Mecury Vapor Bulb
Changed 14 Dec 2012
Runs 7 days a week for 12 hours from 0700 to 1900(7:00pm)

Readings @ 350hrs
LUX @ 10" 5300, horizontal from the center of the bulb's beam @ 1" 5000, @ 2" 4300, @ 3" 2600
UVB* @ 9" 77uW/cm squared, horizontal from the center of the bulb's beam @ 1" 60, @ 2" 55, @ 3" 35
Temp on branch @ 12" 96.6 degrees Fahrenheit, horizontal from the center of the bulb's beam @ 1" 93.2, @ 2" 86.1 @3" 84.1

* I’m utilizing a Solar Meter 6.2 UVB meter to record my measurements. This is a broadband UVB meter which means it takes readings from the whole UVB spectrum (280nm-320nm). D3 photosynthesis is in the range of 290nm-315nm. For this reason I cannot accurately tell if the UVB measurement is in the D3 photosynthesis production range.


Based on these readings you can see the distribution among the entire basking zone is not even. Those that have read my post have noticed I refer to the basking area as a basking zone. This is due to the fact a zone is the entire footprint of a stretched out slider, a fully stretched out female could have a 15-16” basking zone. A basking area refers to the area of the basking spot, i.e. beach, rock, log.

First I will talk about the LUX. LUX is the measurement of light. LUX is closely related to UVA. If the LUX is uneven, than the UVA would be uneven as well. UVA is important, as in, our turtles are able to see in this light spectrum (320nm-400nm). If this is variable then it could have an adverse effect on the physiology of our turtles. Their vision is being greatly despaired. To fix this we would need a High LUX light source.

Next we have the UVB. We know this is important for the process of D3 photosynthesis. I have written an article about this process already on these forums. With uneven UVB the max UVB exposure would be on the shell. It has not been proven or validated that a turtle can absorb UVB thru his/her shell. This is why we see our turtles stretch and flatten their limbs towards a light/heat source. Based on my readings the UVB exposure is greatly reduced at the stretched limbs of my slider. Do to this he moves around his basking zone to get exposure to different parts of his body. A CFL bulb would be guilty of this also.

The heat is an important factor that is also varying throughout the basking zone. This can cause inaccurate thermoregulation of a large turtle. Part of the body is being heated and the other parts are considerably cooler. I have requested permission to show an illustration of this in I/R view, as soon as permission is granted, I will post the illustration to this article.

None of these are encountered when basking in the wild. In the wild a slider that is basking on a log in a stream, river, pond, lake or a sandy, rocky beach would be exposed to direct unobstructed Sun light. Providing even distributed heat, LUX and UV to the turtle. This is something us keepers are always trying to replicate or at least improve to better replicate the sun. To fix this issue we could run multi-light systems. I’m currently guilty of these issues. For example a Halogen light could be used in conjunction with a Metal-halide UVB bulb. The Metal-Halide at a higher height would produce the LUX and UVB in a larger footprint, the Halogen heat bulb would produce the heat for the entire basking zone. The most common why to fix this is run a UVB Fluorescent tubes the length of the basking zone. Then use multiple halogen basking bulbs to heat the entire basking zone. This would still require a non-UVB full spectrum fluorescent with a high LUX output. I feel a MVB could still be utilized as well but would require an additional bulb and a non-UVB fluorescent producing high outputs of LUX. UVB producing tubes and compact fluorescent bulbs do not produce a high output of LUX due to the coating used on the glass to produce the UVB. Even a Mercury Vapor Bulb doesn’t produce the amount of LUX required for their vision. This is the issues being explored and researched every day by herpetologist worldwide. Lighting for reptiles has improved considerably over the last decade or so, but we have a way to go still. One bulb to solve all is not quite here yet.

[ljapa]

* I’m utilizing a Solar Meter 6.2 UVB meter to record my measurements. This is a broadband UVB meter which means it takes readings from the whole UVB spectrum (280nm-320nm). D3 photosynthesis is in the range of 290nm-302nm. For this reason I cannot accurately tell if the UVB measurement is in the D3 photosynthesis production range.

Well according to their site, the model 6.0 was responsive in a bell curve that looks like it peaks at 285nm, so the readings are probably indicative of 290 - 302.

http://www.solarmeter.com/images/SM60graph.gif

I'm curious why you have the UVB measurements at 9" and the temp at 12". Also, given the UVB readings I've seen reported for sunlight in various reptile forums, isn't an mvb going to be too hot if you get it close enough for a higher UVB? How quickly does the UVB drop off as you get further from the bulb?

[slider_keeper]

Sorry that was a typo on my part, the D3 photosynthesis is in the range of 290nm-315nm.

To answer your questions ljapa.
The 6.2 UVB meter (which I own) is a broadband UVB meter meaning it reads the whole UVB spectrum from 280nm to 320nm. This is a wider range than the photosynthesis range, meaning the meter can read both inside the photosynthesis range and outside of it. I'm only pointing this out for research porposes because I can't tell what UVB nm is the highest reading the meter gives. I hope that makes sense. Again sorry for the typo!
Second the meter sensor sits on top of the unit's housing so I have to set the untis housing on top of the basking branch and read the reading this is about a 3 in. difference. from the sensor of this unit and my other instruments to the bulb surface. The branch surface is about 14 in. from the bulb surface to put the bulb surface about 12 in. from the top of my turtle's shell. Again I hope this makes better sense.

[slider_keeper]

I fixed the initial typo from 302nm to 315nm in the orginal post via edit.

[cutepanda86]

Unfortunately, I put another bulb in my setup and Sheldon will bake. I don't have the room for that nor the water depth, it's hard to keep the water the right temp, as it is.

I appreciate you posting this though as when I do get a larger setup, I will look into multiple bulbs.

[slider_keeper]

cutepanda how big is sheldon? What size is his tank?

[cutepanda86]

I have a 15 gallon setup right now. Sheldon is 6". He needs a bigger tank soon but I have no room at the moment, nor the funds to be honest. I hope to upgrade him, later this year though.

[slider_keeper]

Hmmmm.... I know how it is but he really needs more swimming room how about a storage bin at Walmart? At 6" he would require a 8-9" basking zone. I truely feel you on the funds tho! Do you have a Petco near by they have a deal till for a $1 per gallon till the 18th. It goes up to a 55 gal if I'm not mistaken.

[cutepanda86]

I do have a Petco near me. Space is still an issue though. I have nothing that would support a 55 gallon tank and I would need to add furniture. However, when I get a different place, I can do what I need to.

[slider_keeper]

I hear ya, you know what you need;) Hopefully soon. Glad Sheldon is recoving nicely!

[cutepanda86]

I'm crossing my fingers. Thanks! He and I are glad too. ;D