Any heater can malfunction, and it will. The Stealth, Ebo Jaegers and Hyadors all work fine but alll need to be checked.
Having a very inexpensive Thermometer on or in a tank is just smart. Check the Thermometer a couple of times a day.
Your hand is very sensitive to correct temps so at least once a day check your tanks temp and do something about it if it is off one way or another.
Two Heaters in a tank is better than one. Smaller Heaters take longer to get Temps to dangerous levels, which give you time to react, and it is very unlikely that two heaters will go bad at the same time. One heater should be set at just below the other. The submersible Heaters are the only way to go. I have had very bad luck with the bolt ons, in fact the only way they get sold at Auctions is if they are boxed with something else. The main way they get into the Hobby is via kits but those inexpensive Heaters can be very costly.
Having a very inexpensive Thermometer on or in a tank is just smart. Check the Thermometer a couple of times a day.
Your hand is very sensitive to correct temps so at least once a day check your tanks temp and do something about it if it is off one way or another.
Two Heaters in a tank is better than one. Smaller Heaters take longer to get Temps to dangerous levels, which give you time to react, and it is very unlikely that two heaters will go bad at the same time. One heater should be set at just below the other. The submersible Heaters are the only way to go. I have had very bad luck with the bolt ons, in fact the only way they get sold at Auctions is if they are boxed with something else. The main way they get into the Hobby is via kits but those inexpensive Heaters can be very costly.