Before you jump into buying a turtle, look up their setups, regarding lighting requirements, diet, care and setup, as your current setup probably would be in appropriate to house turtles. Everyone seems to be jumping on turtle bandwagons at the moment, and I would heed you all to stop. Even the setup in the previous pictures although it looks nice and may be working for the owner, would be by most keepers, be deemed completely inappropriate. They are a lifetime pet most living over 50+ years and may require high priced vets bills if you want to keep them that long. Please do some thorough research before considering this.
Turtle tanks should have open tops, to allow free movement of air and not allow any condensation to build up. They need to be kept at specific temperatures, water land and air humidity all at different levels depending on the species of turtle. Equipment such as lights can be costly and should be replaced every 6months to a year.
Lots of research will show you also any full grown turtle will be too big for the tank, so you will be upgrading if you get one. It may take them long periods to grow but just like we recommend with fish, think of adult size and requirements rather than baby size when purchasing. A dinner plate size turtle for example will need alot of room, even some of the smallest, musks for example grow to around 6-10" round. That's still large, so think of the hiding spaces and room something that large would eventually need.
Hope it helps; research research and more research please people.