As long as your weather is warm, then get them outside for the uvb. That will save you money on not having to buy that light, they are not cheap. Now just get a regular light bulb, about a 60 watt and hang this over the turtle dock you make so they can get out of the water and bask. They have to be able to get warm enough to digest their food. RES also need to eat in the water, which makes their water dirty fast, so water changes are a must, unless you have a very good filter on the tank, which I am going to assume you don't. If you do get them outside, be sure they also have shade, so they don't over heat in the sun.