what heaters for 200l tank?

[humdingerx]

I am thinking of switching to 2 heaters for my 4ft long 200litre tank to help with more even heat distribution but primarily for safety/failsafe.

What size should I look at for each? The temp delta between ambient room temp and target tank temp is under 10c.

I basically want to know best case to avoid cooking fish if one sticks on, if at all possible?

 

[livewire]

General rule of thumb is 1watt per litre but I tend to try and go with 1.5watt per litre just so that the heater is not over worked. Saying that my tanks break my own rule!

On my open top 180L tank I run a 300W Hydor External heater running off one of my 2 EX1200 filters, the large open water surface means a fair bit of heat is lost so the extra power is required. I run a 200W Hydor on my 60L tank with no problem, reason being that it is also running an external filter and the Hydor heater is not made in anything less that 200W. I know the risk of the heater sticking on is there but in all my years of fish keeping I have never had a heater stick.

I wouldn't go back to an internal heater ever again unless I was running an internal filter and had no option, the heat is distributed much more evenly with an external heater. A well placed internal filter will also do a good job.

 

[humdingerx]

I found out after this thread I can get temperature controllers too which basically cut the power if the water temperature gets too high so I think I'll get one of those for peace of mind

 

[sciencefiction]

The only time I had a problem is when I put a 200W heater on a 100litre tank. I couldn't get the temp down, it went high tropical range all the time and although my fish were doing fine, I just didn't want it that high for oxygen reasons. Now I don't overdo it heater wise unless I need that kind of temperature.
So my advise is, get one heater anything between 200-300w for this size of tank and it should be fine. I've never had a problem having just the one heater in long tanks though it would be a good idea to have a spare one if you want to up the temperatures for one or another reason on temporary basis.
Also, heaters tend to get weaker over the years. My old heater in one of the tanks can only keep up the temp to 23.5 C these days though it's set on 27C. My fish totally don't care about the change and are healthy although they've been living about 4C below recommended temps. I think the range for some species is totally irrelevant unless you want them to breed.

I've read about heaters getting stuck and cooking fish but my heaters either just weaken to nothing or stop working altogether. I think the external ones are a bit nastier. I did cook fish 15-20 years ago but at the time the heater had no thermostat so I had to switch it on and off, lol