What Heaters are You Running?
 

As I have had a heater fail and somewhat fry my tank I now run multiple smaller heaters on a separate controller to avoid that problem again. Both the controller and heater thermostat would have to fail. With smaller 100 watt heaters one broken heater shouldn't be able to increase the temperature too quick in the tank.

From what I have heard is you should replace heaters once every couple years. I primarily use 100 watt eheim jager heaters and by a bunch of them when they go on sale on Boxing day.

Heaters
 

I went to titanium even though they are more money and occasionally they fail but I have had 2-Pro 250 W bust open and take out almost all of my corals. It could have been a power spike but the titanium 1 I had was fine , so even if they fail they don’t crack open I hope and put what ever that stuff is into my tank.
They all make me nervous a bit like you said

I was leaning toward this idea, I have a 300g so I was thinking of buying maybe the 200w or 250w but a bunch of them with a separate controller. I just look at the price being more then 2x for titanium...ugh.

I agree that the titanium tube itself will stand the test of time, however is it worth the money when they will all fail? I guess maybe I have been lucky but I have never had a glass eheim Jager break on me.

I have 2 X Finnex 500W Titanium heaters, with electronic temp control & Guard. For $56 each, you can't go wrong for the price. Although I have usually used them with apex control, I have also used the 150W version on my nano with just their electronic control, and it stays pretty consistent. I have been running all of these on all my systems now for about 3 years and all of them still work well.

I heard that the Cobalt Neo-Therms are very reliable, however at their price point, you could buy 3-4 of the titaniums for that price.

I really think that the Titanium run by an aquarium controller is the way to go.

I have 1 Finnex 500W Titanium heater, with electronic temp control head. I use it as a complete standalone setup, but plug the head into my apex power bar. I set the outlet so that it will turn off should the water temp rise above 2 degrees. Just a bit of a safety feature.

I have a Finnex controller and it runs 6 degrees off right out of the box. It is great at controlling the temperature steady but don't trust the reading. I currently have it set at 84 degrees. I keep all my tanks at 78. I use a Vee Gee digital thermometer to check the precise temperature in all my tanks twice a week. I have done this after I had false readings from glass thermometers and fried a bunch of acropora and killed some fish (lack of O2).

This is why you can never really trust anything out of the box to be honest. I will always go with the titanium element with an external control source.

BRS Investigates actually just had a great video about this. They investigated a bunch of different options. Their best option was the Aquacontroller with a titanium element. You should check it out, it was a good watch.

was running 2 x 500 W heaters on a DA controller on big tank

now running aqueon preset heater on frag tank with thermometer for reference check

4x300w eheim controlled by apex. old school but I haven't found anything better