UVB Lighting Question for Egyptians

ILikeTortoises

New Member
Joined
Oct 8, 2020
Messages
14
Location (City and/or State)
Carlisle, MA
Hi all -

I'm setting up a terrarium for Egyptian tortoises, and was wondering if my lighting set-up is adequate. My terrarium is 48"Lx24"Dx16"H with an interior 36" lighting ballast w/ aluminum reflector housing an Arcadia 34" 6% UVB T5 HO bulb, which sits about 12" from substrate. This gives me a UVI measuring of about 4-7 maximum directly beneath the light bulb, decreasing to about 0.5-1 in the periphery of the enclosure (I tried the 12% UVB arcadia bulb that's listed for "desert species", but at this proximity to the substrate it gave me UVI readings of 8-14). For spots, I currently have two 50w fluorescent bulbs though this gave me surface temp readings of 113-133F, so I've ordered 25w to replace them (these are full-spectrum though only 3% UVB). Will that amount of UVB be adequate for these guys?

Any tips or advice much appreciated - thanks!
 

Tom

The Dog Trainer
10 Year Member!
Platinum Tortoise Club
Joined
Jan 9, 2010
Messages
63,269
Location (City and/or State)
Southern California
For spots, I currently have two 50w fluorescent bulbs though this gave me surface temp readings of 113-133F, so I've ordered 25w to replace them (these are full-spectrum though only 3% UVB).
This does not compute.

50 watt florescent spots that make UV? Unless some new products have recently hit the market that I don't know about this doesn't exist. Are you talking about mercury vapor bulbs?

The UV from your Arcadia bulb is all you need. I'd set that on a timer for 1-2 hours mid day only. Use LED lighting, and a low wattage incandescent flood bulb for basking. Adjust the height of the basking bulb to get the correct temp under it.

You should not need indoor UV for most of the year. Make a safe, secure outdoor enclosure for real sunshine when weather permits.
 

ILikeTortoises

New Member
Joined
Oct 8, 2020
Messages
14
Location (City and/or State)
Carlisle, MA
This does not compute.

50 watt florescent spots that make UV? Unless some new products have recently hit the market that I don't know about this doesn't exist. Are you talking about mercury vapor bulbs?

The UV from your Arcadia bulb is all you need. I'd set that on a timer for 1-2 hours mid day only. Use LED lighting, and a low wattage incandescent flood bulb for basking. Adjust the height of the basking bulb to get the correct temp under it.

You should not need indoor UV for most of the year. Make a safe, secure outdoor enclosure for real sunshine when weather permits.

You are right. The basking bulbs are UV halide, marketed as 3% UVB/97% UVA. The 50w ones I currently have create too hot of a surface temperature and I don't have any room to move them higher as they're mounted inside the terrarium. So I've ordered 25w which come tomorrow so hopefully the surface temperature generated from those will be around my goal of 95F.

1-2 hours of UVB seems inadequate, no? Most every source I read for this desert species recommends 10-14 hours of full-spectrum daylight depending on the season, with 6-10 hours of basking light hours.
 

Tom

The Dog Trainer
10 Year Member!
Platinum Tortoise Club
Joined
Jan 9, 2010
Messages
63,269
Location (City and/or State)
Southern California
1-2 hours of UVB seems inadequate, no? Most every source I read for this desert species recommends 10-14 hours of full-spectrum daylight depending on the season, with 6-10 hours of basking light hours.

No. There are a LOT of misconceptions about what our tortoises need, and this species is no exception. In the wild, they don't bask in the heat of the days for 10-14 hours. They hide from the sun and seek cover in shaded, higher humidity areas. They come out only in the early morning and late evening when UV levels are at zero or very low. There isn't 10-14 hours of UV levels of 4-7 in the wild in summer. There is a mid day spike, and levels are zero or low until late morning, and then drop back down in the afternoon. Don't take my word for it. Take your meter outside and see for yourself. There is almost no UV until around 9:30-10am this time of year. By 4-4:30, its back down to zero again in full hot direct sun.

For any light colored species, 30 minutes once or twice a week will meet their UV needs. If you also feed some Maruri, and use a calcium supplement with D3, you'll never see a hint of MBD. Black species, arguably, need more time outside in the sun to get the same amount of D3 made.

If you have the Arcadia bulb, you don't need those other UV bulbs. UV bulbs contribute to pyramiding. Almost every Egyptian I've ever seen is pyramided. Between the overly dry enclosures, hot lamps, and excessive UV, I don't see the trend reversing anytime soon.

This is new info that some of us have been working on. I haven't used any indoor UV for quite a long time now. Not with any of my species. We are in CA. We don't need it. We have real warm sunshine all year long. I put the torts outside two or three times a week. One hour for hatchings, and a few hours for older tortoises depending n their size, and I soak them all on the way back in to rehydrate them and their carapaces after being out in the warm dry air.
 
Top