redearslider.com

My turtles never bask under my UVB light. They will bask together under the heat light though. Is it normal for no UVB basking?

Your UVB light source should be directed towards the basking area. They will always pick the heat over the UVB light, they'll just get cold under the UVB. Find a way for them to be directed in the same place.

We keep our basking light centered on the platform but the hood for the tank houses the UV light so they are impacted by the UV while basking and swimming.

JAX is right - both the heat bulb and the UVB bulb should be pointed at the same place - the basking platform. If you're using a tube fluorescent for UVB, then just be sure it's positioned low enough and that the basking area is directly under some part of the tube. What motivates turtles to bask is heat - they are natural born heat seekers. Once we capture their attention with the heat bulb, we then focus the UVB light on them because it's good for their health.