First, whatever you do, stay away from the Jalli titanium heaters. The last one I had lasted for 48 hours and then died. I have also used the Catalina Aquatics 500W titanium heaters (available on ebay) and so far, so good. The CAs are nice because they don't use a separate temperature probe...it's built into the titanium module, like a conventional heater. The Stealth is an excellent heater but has a maximum wattage of only 250 watts, which makes it undesirable for large tanks.