So today, bc it's starting to get cold here and the torts will start living inside for awhile I started a little research and am somewhat aggravated by what is offered on the market as far as UVB is concerned. I have went in the past with the UVB Mercury vapor bulbs by zoo-med but this doesn't allow for the tortoise to bask without getting UVB rays. I also run T5 high output tubes in my enclosure but while researching have found that the 5.0 and 10.0 tubes only offer 5% and 10% UVB output. I ran the question of why is it that in a reef aquarium setup does one have to use 300 plus watts of 10,000k and 460 nm to provide enough light to sustain a reef in a 75 gallon tank for proper calcium absorption in coral then how in the world does one replicate the sun in a 4'x4' enclosure for a tortoise. So I googled my question. (T5 lights provide UVB.) what popped up discouraged me. It talked about lumens and the UVB concentration of natural sunlight compared to products on the U.S. Market and as the consumer we are being ripped. I'm literally at wits ends over this. The Arcadia bulb out of the UK offers 12% and is the closest bulb that replicates natural sunlight when being paired with a 6500k day light tub. As far as heat then provide heat emitters for gradient heat and a lower watt normal basking light for extra warmth a sunning. Anyone care to chime in on this?