# How many watts should a heater be for 125 gallons?



## JWhipple (Jun 20, 2007)

I just setup a 125 gallon tank and just realized - I don't have a heater for it!

How many watts should I go with?

Thanks!


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## pbyrley (Jan 23, 2008)

This was for Stealth heaters.

Wattage Length For Aquariums
25W 8-1/4" 8 gallons
50W 8-1/4" 15 gallons
75W 10" 25 gallons
100W 10" 30 gallons
150W 13-3/4" 45 gallons
200W 13-3/4" 55 gallons
250W 15" 75 gallons

So it looks like you could use two 250 watt or three 150 watt heaters to me. Maybe someone with more experience will suggest a decent power head to make sure the water stays mixed (no hot or cool spots).

I know how warm Merritt Island is so consider the lowest temp in your aquarium room. My aquariums are in my garage and it can get cold so I use much more watts with two heaters per tank and I have small tanks.


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## Vincent (May 7, 2004)

There was a thread about this recently and you can probably find it by searching. For me, one 250W or 300W heater would be sufficient.


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## jzyjack (Dec 31, 2008)

I have a hydor 300 watt inline external heater in my 110 and it is more than sufficient.


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## scrivz (Dec 2, 2008)

I like redundancy in case a heater fails me, so I'd probably go with two 250W stealths. That way if one goes down the other can probably handle it until you can replace the dead one.

Never had stealth fail on me, though. :thumb:


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## JWhipple (Jun 20, 2007)

Thanks guys! I just ordered a pair of 300w heaters off of Ebay for some redundancy.


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## HiImSean (Apr 5, 2007)

i have a 250w and a 200w in my 125g. keeps it heated just fine


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## JWhipple (Jun 20, 2007)

It's not like my tank will require a lot of heating. Even now during the winter it doesn't get any colder than 70 degrees inside my house and the lowest I've seen the tanks get is 72 degrees (as they were this morning).

I'd like to keep it at at least 76 though - with two at least then if one fails the other will be able to handle the job.


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