So I've been trying to get things ready to upgrade Herman's tank to a 75+ gal setup, but I've come across a troubling trend. I'm currently using a 50 or 100 watt Marineland Stealth Heater and I'm pretty satisfied with it. Herman likes to wedge himself between the corner and the heater and go to sleep at night, and since it's basically unbreakable I think it's a pretty good item. Thus when I was planning for upgrades I was thinking I'd just get a larger Stealth heater for the appropriate gallonage.
Problem is, on several different websites I've seen aquarist user reviews where the thermostat broke on the heater and basically cooked their fish. This may not be as big a deal with Turtles as if they get too hot they could retreat to their basking area, but this still concerns me since it may not be immediately noticeable and could lead to hyperthermia in our little friends.
So has anyone here had any problems with the stealth heaters or know someone who has? Does anyone have opinions on whether they would be relatively safe given the ability of turtles to leave the water? Does anyone have a recomendation for a different brand of non-breakable heater? I've heard a bit about titanium heaters, but not much, and not what kind/which brand to look for. Thanks for any input!

