one more question on heaters

[valiko]

Ok.
Given - 50 gal tank.
What is better?
2 x 100 w heaters or 1 200 w?

[darkdep]

2 x 100w, in my opinion.

Reason:  A failure of one will have a less drastic effect on the tank and will give you a window to replace.  

But, you have two pieces of equipment in the tank, which could bother some.

[mseguin]

Persoanlly, I would go with the 200 W. Just make sure you have good flow.

[valiko]

I've never thought of that.

Let say you've got 2x100 heaters and one of them fails. Then shortly the second one will fail too, since it will be on all the time?
Am I right?

So why is it suggested everywhere to have 2 heaters?

[Mettle]

I'd do two 150w heaters personally. But that's just me.

I have a single 200w in my turtle vivarium, but it's only got approximately 30 gallons of water in it.

And I think the idea with the two heaters is that you'd figure out that one was shorted/broken before the second over worked itself.

[darkdep]

Well, assuming you devote the recommended 2 seconds per day to read your aquarium thermometer, you probably know the rough temp of your tank.  If one of the two fails, you'd likely notice an issue when the temp had dropped only a couple degrees, before any serious livestock damage could occur.

The other "failure" heaters go through is getting stuck ON.  With 2x100, one being stuck on would take longer to nuke the tank and again, you'd notice a slower temp increase.