Q about lighting..

[Martin Martinussen]

Martin, please stop giving UV advice until you have learned a bit more. You have gotten yourself way off track and totally misunderstand most of the things you are referring to.

Where to start????

First. the 2.0 and 5.0 and 10.0 and 12.0 that bulbs are rated has NOTHING to do with the UVI index they produce. Those numbers are the percentage of UVB radiation on the total electromagnetic radiation the bulb emits. Roughly, a 10.0 fluorescent tube will be emitting 10% UVB, about 30% UVA the remaining 60% as visible light. A 5.0 tube emits 5% UVB, about 35% UVA and 60% visible light, etc, etc. The marketing mumbo jumbo about forest, desert, etc is pure marketing talk. The DISTANCE from any of the bulbs controls the UVI reading you will get. So with a standard 12.0 bulb (not HO), you will probably get a 3-4 UVI at about 16"-18". With a 5.0 bulb you will probably get a 3-4 UVI at 8"-10". A reflector hood will change those numbers dramatically.

To try to emulate "what they get in the wild" is a slippery slope. First, sulcatas are not from the Sahara. They are from the Sahel - the grasslands that border the southern fringes. To say that a solar noon you can get a UVI reading of 13 in the Sahel is true. But that is the same as saying in the summer you can get a temperature of 130°. So are you trying to set up your enclosure to be 130° with a gradient? OF course not. A sulcata would die in 130° heat and is deep in its burrow at such times. Even here is N Califonia, my sulcatas truly bask, with legs stretched out, pretty much around 8-10AM in the morning only. In the wild, you would probably see a sulcata (or leopard) basking around 8-9AM.

The standard worldwide for UV index was created to have a universal way to talk about the "sunburning" strength of the sun so it could be related to different parts of the world and still apply. The scale standardly went from 0 -10, but more recently most scales now include 11.0. They only go to 11.0 because anything above that would fry you in less than 3 minutes, and you should never expose your skin to a UVI that high. For comparison, the MAXIMUM UVI reading you can get at solar noon, June 20th would be:
Miami Florida - 10.0-11.0
New York, New York - 6.0-7.0
Portland OR - 5.0-6.0
Anchorage Alaska - 3.0-4.0
If you look at the Max UVI for Niger this week (where my several of my sulcatas came from) it is 12.0.

The best charts I have found in all my studies that seem to give the best guidelines for UVI levels for reptiles in captivity is the Ferguson zones. I have used these guidelines in setting up my lighting for some time now. Here is that chart recently revised:

View attachment 214094

So you can see the best recommendations we have on the UVI zones we should create for our tortoises would be the high end of the zone 3 = a gradient from probably 3.5 - 7.0. I personally do not believe the higher end is necessary at all, and I go for a basking zone of 3.0 - 4.0 in my enclosures for sulcatas, leopards and for the stars.

They do not need much UVB at all to satisfy the needs for creating the pre-d in their skin. A few minutes in a 3.0 UVI a few times a week would do it. They more commonly bask half hidden in shade. For example, tight now, mid summer at 1PM (solar noon with daylight savings) I get a UVI of 9.0 in full sun. But 2 feet into the shade, where it is more comfortable, I still get a UVI of 1.5 - 2.0. That is enough for a tortoise to properly start synthesizing pre-d in probably 15 - minutes time. The chemicals in the pre-d conversion process also carry a lot of other health benefits to the tortoise, and they have a longer life in the bloodstream than most viatamins. So proper exposure will create levels in the bloodstream that will carry the tortoise through several weeks of no UVB exposure if conditions change.

The gradient created by giving zones of 4.0 all the way to 0 is beneficial, and hatchlings in particular would never really bask in full sun. They would obtain all their UVB and pre d synthesis needs sitting under cover of bushes where they probably are getting an effective UVI of 2.0 or so. So, again, what are you trying to duplicate "from the wild"?

Advocating the use of UVI card readers is quite a dangerous proposition. In fact, there is no other meter on the market I would personally trust my tortoises well being with than the solarmeter 6.5. Even their solarmeter 6.2 can be misleading to use. It is a very costly and laborious production to make a meter that reads specifically the wavelength of light needed for D3 synthesis. A complex algorithm must be incorporated to produce a reading that applies to that specifically. All the card readers and other meters read strength of UV radiation, but that does not mean the 297nm wavelength is in the light being emmited at all. IN fact, the big problem detected with the early compact fluorescent bulbs was only finally resolved by the use of the solarmeter 6.5. The 6.2 was the meter of choice back then and gave perfectly fine readings. But when the new 6.5 that was created to specifically weight toward the 295nm wavelength was used, it was found that some compacts were emitting 5 to 6 times the 295nm light as they were supposed to. The "total" UV reading was fine, but when the actual D3 producing wavelength was more isolated, a big problem was uncovered.

I just last month, actually had my meter recalibrated by solarmeter, just to be sure everything is correct. In a personal conversation with the guys designing these meters, they stated they would never trust a meter, or certainly a card, knowing what is involved in getting actual, meaningful results our tortoises' lives and well being count on.

 

[Martin Martinussen]

Where did you see me giving advice.. only said that the UV card is a fine Indicator.. if you don't have 300$ to buy the UV meter. So I said if it showes 9or10 it didn't matter.. should have said 1 or 2maybe but now the reading wasn't the issue.

But I still thought the UV output was alot higher on the tubes.. yeah my bad.. was thinking about the output where they live. And that's way higher.. then its around 1UV even for a dessert tube 35cm away..
As shown in the test I linked.. with the 12% tubes Tom is using

As you point out the younger turts don't bask alot.. that's why I was asking about putting up 2×20w tubes or 1x40w as Tom said. Over there garden enclosure since they are inside most of the time..
So basicly just trying to get then some UV when they are hiding in the "shade".. like they would get in the wild..

Fyi the garden enclosure is also inside.. Why I want UV over it.. and then they have the humid enclosure with there basking spot inside connected to it.. So they can go from one to another.. see pic..

 

[Markw84]

I use a UVB 10% tube 14W at about 25 cm height above ground. Is it OK to have it on all day, or should I only have it on during mid day? It's a pretty new tube so it should be at its best.

UVI is a lot easier to understand than wavelength. The Ferguson zones makes sense of it.

I personally believe that if you have a good, color balanced light for ambient light, the D3 portion of UVB needs is easily covered in a few hours of artificial UVB source a day. I, like @Tom, keep my UVB on 4 hours midday. I mount it where I get a UVI of 3-4 over the basking area, and I have the feeding area where it is getting 3-4 as well. I have pots with overhanging plants all around the borders of the basking zone creating a secure, "hiding" spot where there is still a UVI of about 1-2. My stars, leopards and sulcatas do well in that arrangement. My sulcatas and stars bask more than my leopards. All use the "hiding spots" all the time. I personally don't agree with the higher parts of the Ferguson zones. From what I've studied of the way that was created, they looked at the readings where reptiles will bask in a wild setting. However, it does not take into account how long a reptile will bask in those areas, vs take shelter. In a captive environment, I believe it best to therefore give ample opportunity and space to get away from the UVB, and limit peak UVB times.

I cannot help but think of my kids, and now grandkids, as we take them out to enjoy the pool. I would never allow then out all day, unprotected in the sun. although a little is a good thing, it is easy to overdo! Baby leopards seem so prone to eye issues. I can't help but think many of the times that very well could be a reaction to "too much sun" In the wild, they are so cryptic. In captivity we need to be sure our temps are correct, or we are creating a situation where they may bask for thermoregulation, to get body temps up, and in the process be forced to sit under UVB way longer than they would normally.

This of course, does not take into account the value of good ambient lighting and the importance of UVA for metabolic rhythms, etc. A good UVB tube is also producing even more UVA than UVB. That is why I have gone to using good quality 5000k - 6500k lights with a CRI above 90 for ambient lighting in addition to the UVB tubes. Since I limit UVB exposure, I do need to ensure a more natural ambient daylight and day period. The above 5000k I refer to as it will then have more blues in the spectrum which is important for circannual rhythms and well-being. It also helps tremendously with plant growth in your enclosure. The above 90 CRI (color rendering index) is the total color balance of the light across the spectrum. Sometimes a 6500K light many have way too much blue and has lost a lot of the reds. Reds are important for circadian rhythms, so we want the whole spectrum.

So... FINALLY! Your 10.0 is, I assume an 18" tube if 14 watts. I don't know if you are using a reflector hood. That tube normally will be recommended by manufacturer to be hung from 25cm - 40cm above shell height. Since you are using 25cm, I would ASSUME that you are getting the higher end of the recommended UVI strength with a new tube at that height. Since you are guessing and not using a meter to check, I would err on the side of caution and go more in the 35 cm height. Since it is a leopard tortoise, I would personally also limit the UVB time to midday. We are not only limiting UVB peak exposure, but also simulating better a midday peak nature would provide.

 

[Reptilian Feline]

Thank you Mark for such an excellent explanation to light and UVB.

So... FINALLY! Your 10.0 is, I assume an 18" tube if 14 watts. I don't know if you are using a reflector hood. That tube normally will be recommended by manufacturer to be hung from 25cm - 40cm above shell height. Since you are using 25cm, I would ASSUME that you are getting the higher end of the recommended UVI strength with a new tube at that height. Since you are guessing and not using a meter to check, I would err on the side of caution and go more in the 35 cm height. Since it is a leopard tortoise, I would personally also limit the UVB time to midday. We are not only limiting UVB peak exposure, but also simulating better a midday peak nature would provide.

I've placed some aluminium foil above and to the side of the tube light as reflectors. He can hide under a plant, under the bridge or in or behind his hide. I can't place the tube any higher at the moment because of the box size, but I'll keep your recommendation in mind when setting up a more permanent home for him if all goes well.

I've been thinking of getting those LED grow lights. Saw some at IKEA the other day, usable in normal fixtures. I think something like that would help a lot in a bigger enclosure. First the grow lights go on, then an hour or so later the basking solar flood light (says on the box it has UVA), and then around noon, the UVB tube. Does that sound OK? Reverse in the evening.

I'll put the UVB tube on a separate timer and have it on for 3 hours a day to compensate for the low hight and reflectors.

Sorry Martin for changing the path of this thread a little, but I think Mark's answer can help you too.

 

[Markw84]

Thank you Mark for such an excellent explanation to light and UVB.



I've placed some aluminium foil above and to the side of the tube light as reflectors. He can hide under a plant, under the bridge or in or behind his hide. I can't place the tube any higher at the moment because of the box size, but I'll keep your recommendation in mind when setting up a more permanent home for him if all goes well.

I've been thinking of getting those LED grow lights. Saw some at IKEA the other day, usable in normal fixtures. I think something like that would help a lot in a bigger enclosure. First the grow lights go on, then an hour or so later the basking solar flood light (says on the box it has UVA), and then around noon, the UVB tube. Does that sound OK? Reverse in the evening.

I'll put the UVB tube on a separate timer and have it on for 3 hours a day to compensate for the low hight and reflectors.

Sorry Martin for changing the path of this thread a little, but I think Mark's answer can help you too.

I actually like the LED lights and use them in my night box for my star tortoises to create a photoperiod that I vary with season. Some of my tortoise stay in the box a lot during the day, and I don't want darkness during they day they would not experience in the wild. Also, on cooler days I may have the box closed as it is too cold for them outside, yet I want to maintain the circannual and circadian rythyms. I cannot use any incandescent or fluorescent with ballast as it overheats the box on warm days. The LEDs add practically no heat what so ever. I am just careful to get LED lights with a good CRi and 5500k or so.

Check the color temp of the grow lights you are looking at. I like them and like the benefit for enclosure plants, but sometimes have to add other lights to balance the color. Often grow lights are quite blue in overall color balance. But in an indoor enclosure, the incandescent basking bulb balances that out nicely. I like the combination and timing you are describing.