This post is a mish mash of quasi-free form rambling.
First, what started it: I live at the northernmost natural range for RES. On the daily walks for the dog, I frequently go by a pond that has RES, painted turtles and snappers. There are few good basking areas, but I do see RES and painteds on the few that are there. I see many many more floating at the surface.
At work, we border a pond with tons of great basking areas in fallen trees cluttering the pond. I see many basking turtles, even stacked turtles.
I see turtles basking at noon at the end of June. Using a solarmeter 6.2, I've gotten readings of 350 at that time. These turtles are basking on water, which means the UVB is reflecting off the surface and hitting the underside of outstretched limbs.
These wild turtles also brumate in the winter under ice, unlike our turtles--and this winter in the Chicago area, that ice got pretty thick. I saw wild turtles first basking when the air temp was in the high 50's.
I know we can't replicate that annual cycle. But, I wonder if we are under providing UVB. My MegaRay is outputting around a max 90 micro watts at its highest point, and that is on my turtles shell, not her skin.
I have a 55 gallon for now with an ATBA on one side. I'm seriously considering a second on the other with higher UVB to offer my turtle the choice. I don't think I can use a MegaRay because the heat would be too high. But, I'm thinking a cfl UVB plus incandescent for heat.
Has anyone tried different UVB level basking areas?
Can anyone further south who sees basking RES in the wild comment on what time of day you see them basking?