I was just googling to find out a good source on turtles and lighting.
I came across this PDF on the reptileuvinfo.com website.
http://www.reptileuvinfo.com/docs/uvb-and-aquatic-and-simi-aquatic-turtles.pdf
The founder of the Mega-Ray bulb line discusses tests that showed water did dissipate the UVB waves substantially, but did not reflect them completely. This was interesting because I was told UVB rays did not give an effect to anything underwater.
Don't Forget! RESs and other aquatic turtles still need to dry their shells out completely, top and bottom, regularly!
