While aquatic plants aren't necessary for a turtle aquarium, they can help the tank appear more natural. Find plants including water lettuce, water lily, water hyacinth, aquatic grass and duckweed at your local pet store. Consider planting rooted plants in the tank's substrate or choose floating plants, such as duckweed, so the turtle won't uproot the plants when moving around.
This video shows how easy and cheap to set aquarium for turtles
Ensure the water temperature is appropriate for your turtles. Red-eared sliders require a water temperature slightly above room temperature, ranging from 74 to 85 degrees Fahrenheit. An aquarium heater or over-the-tank heat light can raise the temperature to the proper levels. Monitor the temperature frequently to ensure it is not too hot or too cold. At temperatures below 70 degrees, turtles become lethargic, and at temperatures below 65 degrees, they stop eating.
Sea turtle rehabilitation - Seattle Aquarium
This page deals with setting up an indoor habitat in an aquarium or "fish tank." Many people build outdoor ponds (or even indoor ponds) for their turtles, and that's an excellent idea if you have the room, the money, and the right kind of climate. But for most people, building a pond isn't very practical. (If you're a renter, the landlord might be very unhappy.)
Tetra Turtle Aquarium Heater | reptile Heaters | PetSmart
Most people keep their pet turtles in aquariums but that doesn’t mean you have to. Anything that holds a lot of water will work. Large tubs, plastic pond liners, and anything you can think of. Aquariums are the most popular because you can watch your pet turtles through the tank inside your house and they are easy to buy and setup.Your turtle will live in water and that water will get very dirty. This is where a fish aquarium filter comes in to save you. Instead of having to change that water all the time, you use the filter to do the dirty work for you. Turtles are dirty pets so the bigger the filter the better. Warning- these can sometimes be expensive.. but save a lot of time down the road and help keep your water clean.