Saw an interesting video on UVB

It's a bit long but WELL worth the time to watch. Made me think a bit different about some things!!!
https://youtu.be/baSGAzSKDOQ

He confirms a lot of what we tend to go over regarding creation of gradients across the enclosures. For reference, I generally recommend 3-6 UVI across the basking area (at least the length of your dragon so about 18-24'' for adults) for bearded dragons. This reflects the readings in mid morning and late afternoon in parts of their natural habitat.

It's definitely helpful to have a Solarmeter to check the gradients and outputs of each individual enclosure and bulb. Not all bulb brands are equal and sometimes the same brand can fluctuate between bulbs (quality control issues) which is why we tend to stick to recommending brands that have a good track record in our setups.

A few things to note about the video. When he measured the T8, he moved the solarmeter away from the bulb rather than along the length of the bulb. His T8 also had lower readings than mine have. The T8 (and T5) tubes produce a relatively even output along their length. If you align the bulb with the length of the basking site, then it produces a nice long area for a dragon to bask under evenly. The downside of using the compact coil is that while it produces a good amount of UVB directly below the bulb, as you move away in any direction, the output drops off quickly. Using two of them side by side can help extend the area of basking level UVB. The compact he tested is a good one and is the proper wattage for a dragon.

Another thing to note is that his MVB was producing a lot of UVB, but he was not taking surface temperature readings. The downside of that is if he moved the bulb high enough to produce 3-6 UVI then the surface temps may not be high enough for basking. This would require use of a second bulb/CHE to produce adequate heat (which negates the all in one benefit). There is also an issue of varying output between brands, so using a known brand to estimate output or having a Solarmeter to measure output of a specific bulb is key. I have 3 different MVB brands running in my house right now and they are all quite a bit different from eachother in terms of UVB output, heat output, and visual brightness even though they are all 100w MVBs. I've taken surface temp readings and UV readings and adjusted the height of each of them accordingly.

At the end, his T5 readings seemed much lower than they should be. I'm not sure which brand he was using or if he was using a reflector (reflectors aren't all the same either). My Arcadia T5 in my main enclosure is almost 5 years old now and is still putting out 4 UVI at 12'' directly under the bulb. The test results that Taterbug reported are helpful to show the output of a T5 under different configurations. https://sites.google.com/site/thelizardmadness/lighting-guides

I think the main takeaways are that it is important to create a gradient of both heat and UVB around the enclosure to provide many options for your dragon. It is important to take into account the type of UVB light you are using and that if something like screen is in the way, it will reduce effective distance by blocking some of the light. It is ideal to be able to have a Solarmeter to measure these readings for sure, but without one it's best to stick with known brands and base your configuration off of previous test results (from other users or the ones posted by Dr Baines).

It is always best to keep up our research and share the things we find on here for others.