I use the "Aqua One" glass fully submersible heaters in my tanks, they are the only heaters I have every used and find them very reliable. I was limited with the choice of heater to get because that brand is the only one that was available. You many find that some heaters do have to be adjusted during summer or winter.
If you have big fish like Discus or Oscars etc. (which you don't obviously Sue) I would recommend the stainless steel heaters..The glass ones could eventually break if the fish keep bumping into them.
Last edited by Bernie : at .