Some Questions

[deadheadvet]

A new bulb should have a reading between 150-300uW/M2 is my understanding. I would have to go back and scan a new bulb to see if that is accurate. They recommend at least 75uW/M2, so 7.1 on the meter could be too low, especially at the height you are using which is pretty low ( can't go much lower)

 

[Tom]

Is it possible I'm not using enough water? I'm trying to get it so it's slightly under his chin and up to the bottom of the shell in the back.

It is possible. I go about half way up their shell. So a 2" tall tortoise will soak in about 1" of water.

 

[ClairDipson72]

It is possible. I go about half way up their shell. So a 2" tall tortoise will soak in about 1" of water.

That would cover his mouth if I went past the bottom of the shell. Will he know to lift his head and not drown?

 

[Tom]

A new bulb should have a reading between 150-300uW/M2 is my understanding. I would have to go back and scan a new bulb to see if that is accurate. They recommend at least 75uW/M2, so 7.1 on the meter could be too low, especially at the height you are using which is pretty low ( can't go much lower)

I'm using a 6.5 meter. It registers the "UV Index". 7.1 is very high. Like mid day sumer sun high. Don't have the exact conversion, but I think this would equate to around 450 microwatts/sq. cm. It did not seem right, so I put my 6.2 meter under it and got a similarly high reading. I wish I could remember the number on the 6.2 meter. Sorry. After 4 years I was expecting it to read zero and I was just using it over a blue tongue skink for heat, since they don't need indoor UV and I sun them outdoors anyway. I set the height to get the correct basking temp. Actual height to lizard's basking rock was about 18" but the height of the meter raises the sensor about 4". So the sensor on the end of the unit was 14" from the lamp, but 18" from where the lizard would bask. I was also expecting the reading to be low or zero because I was using it through the metal screen on top of the cage. After a few more months, this old bulb finally burned out. I don't know what the readings would have been when it was new. I didn't have meters back them. This same bulb did bring a green iguana back from MBD over its first winter though, so I know it was producing at least decent UV when it was new too.

For comparison sake, my 6.5 meter gives me a reading of 6.1 UVI out of my new Arcadia 12% HO 46" bulbs in a reflector hood at 20" from the sensor.

Interesting that your bulbs went to zero so quickly. Something has obviously changed over the years. Sad.

 

[Tom]

That would cover his mouth if I went past the bottom of the shell. Will he know to lift his head and not drown?

Yes. Going by chin height is tough because they can hold their head high or lay it on the ground. I go by their shell.

Also note that to drink they must submerge their entire mouth AND nostrils. This is tough for them to do in water that is too shallow. If you walk up and see his whole head under water and his throat and head bobbing rhythmically, don't panic. He's just getting a drink. Being reptiles, they can hold their breath for a long time.

At halfway up the shell they can simply stand up or raise their head a little and be clear of the water.

 

[deadheadvet]

They are from the last 1-2 years, so possibly like anything else, the older stuff lasts longer.