What we need to buy for Eger

Top Fin Liquid Crystal Thermometer
Easy-to-read thermometer makes it convenient to monitor the temperature of your aquarium. Reads in Fahrenheit and Celsius.

Submersible Heater
 

Acura 1000 Heater
Fully Submersible - Set It and Forget It!

Penn Plax Submersible Heater
Precision engineered and easy to hide.

From Austin's turtle page:

Tronic Heaters
Tronic heaters consistently achieve and maintain desired water temperature by means of its patented Thermal Sensor. Unlike other heaters Tronics state of the art sensor has NO moving components to stick or corrode. Tronic's sensor rests on the glass of the heater tube allowing accurate temperature reading which is transmitted to Tronic's advanced control circitry. Tronic is fully submersible and may be placed anywhere in the aquarium. When removed from water the patented Thermal Sensor triggers Tronic's Automatic Safety Shut-Off. You can also buy a "Heater Guard" which will prevent the turtle from biting or cracking it with it's shell.

ProAquatics
Proquatics Hydrosafe Heaters These are the safest, most technologically advanced heaters available. A thin layer of thermosensitive carbon and organic resins allows for heat resistance that increases along with temperature, meaning that the unit cannot overheat; even if left out of the water. Hydrosafe Heaters should be mounted vertically, and submerged up to indicated level only. Thermostat remains accurately calibrated even if the knob is turned too far; and a digital temperature indicator allows accurate setting to within 1 degree Fahrenheit. Remember that the size of the heater you use is directly related to the size of the aquarium; a general rule is 50 watts per 10 gallons of aquarium capacity. They seem to work pretty good. I've had one in my RES tank for 2 years without any problems.
Visitherm
Visitherm Heaters Double sealed heater is completely waterproof and submersible. Direct read Fahrenheit and Centigrade scale make pre-setting temperatures very simple. Marine design tolerates harsh tank conditions. This heater is super Durable. Great turtle heater
ACURA
Acura 1000 Heater Fully submersible, set it and forget it! Unique ratchet style temperature knob can't be over wound. Heavy-duty heat and shock resistant glass tube. Easy to read red temperature indicator and on/off light.

From Selecting Aquarium Heaters

Note that the use of a glass heater can be dangerous. If the glass breaks, both you and your turtle may be electrocuted. Turtles can be vigorous - be sure to protect the heater from the turtle. A good solution is to bury the heater (it must be the submersible type) in the gravel over an under-gravel filter. The operation of the under-gravel filter will circulate water around the heater. If there is not enough gravel to protect the heater, consider surrounding it with bricks or stones. Some brands have a heater guard that fits around the glass tube and provides some protection.

There are several brands of heaters available. The Ebo Jager heater is considered to be among the best. It is completely submersible, has an adjustable temperature setting knob (although it is difficult to adjust since it is surrounded by the water seal), and uses high quality, shock resistant glass. This last feature is very important - cheap heaters using thin glass tubes will not withstand the onslaught of a vigorous turtle. The Ebo Jager has its temperature setting indicated on the adjustment knob, but you should always check the temperature with a high quality aquarium thermometer, at least until you get the setting correct. Hagen has the Hagen Tronic series that also can be recommended. This series has an electronic temperature control which should be more reliable than the normal bi-metallic strip control mechanism.

When selecting a heater for your setup, do not buy more power than you need. If the heater is too powerful for the size of the aquarium, the heater will cycle more often and will wear out sooner. It is possible, if unlikely, for the heater to fail where it is on continuously. The better heaters have a safety feature that will prevent overheating should the main thermostat fail. You should look for this feature in any heater that you buy.
To make it simple, get an adjustable, fully submersible heater that is the right wattage for the tank. Use a good thermometer to check the water temperature. A good rule of thumb is to use a heater with 4 to 5 Watts per gallon of aquarium size for small tanks and 3 to 4 Watts per gallon for larger tanks. Note that even if the aquarium is not filled, you should select a heater based on the aquarium size since most heat loss is through the top water surface. If you keep your house cool, you should size the heater using the higher wattage number. 

We should get the 100 watt size.  Either Hagen (on sale right now at pet mountain for $11.95) w/ heater guard, or the Ebo-Jager b/c it's pyrex and more durable.  For price compare on Ebo-Jager
 
product w/acriflavin