redearslider.com

well my turtle is basking as we speak, he is still sorta wet. i went and looked at him and there seems to be some bright green stuff on his sheel. like right in the middle and right on the edge. is this algea? and is it bad to have algea in the tank? because with the uvb light there is lots in there.
so is it algea is it bad? and is it bad to have algea in the tank!

It sounds like algae, and algae isn't bad. I've had some in my tanks for a long time, and I just leave it (unless it really gets bad, which it hasn't) because I like the natural look it gives to the tank. Algae is mainly caused by light, warmth and nutrients in the water; alter one of these contributors, and it can make it more difficult for algae to grow. If you do clean it, it will come back fairly quickly unless the surface is thoroughly cleaned. And even if it is, it will return at some point.

I do try to keep algae off the the shell, because it can mask other potential shell problems. You can easily take it off your turtle by wiping it off with a cloth (which is what I do) or with a soft brush to very gently clean the shell.

If you want to try to get rid of it, do a search on algae. There are several threads that have been made on it in the past.