You really need to make sure you rinse all inserts very very well before using them. I have a difficult time with the carbon inserts on my filter... a real pain sometimes
You should have a fully submersible water heater instead of having the lights on 24/7. Turtles should have a day/night cycle like there is in nature. So, no, you don't need a night light
There are many different kinds of floating ramps, zoo-med is the one I think most people use, there's also other kinds, you'll just have to search. This is similar to the one I have.. although I believe it's a different manufacturer.
http://www.drsfostersmith.com/product/p ... =AA&ctt=62
I've had a few different kind and this is the one I like the most.. My turtles are both around 4" and both can fit on it easily. The water level and change and they can still get up because of the long ramp.