# Will a 100 watt heater be sufficient for a 40 Gallon?



## a.wiatrowski (Jan 29, 2010)

I'm finally going to setup this 40 gallon that I picked up almost a year ago. I'm ordering everything for it right now. I want to know if a 100 watt heater will work? As of right now, I've only ordered an aqua clear 70 for it.


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## ndblaikie (Oct 12, 2011)

What do you plan on putting in it first of all?


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## a.wiatrowski (Jan 29, 2010)

I was thinking between 12 and 15 saulosi or demasoni. I'm putting sand and rocks. I haven't decided what sort of rocks but i will provide enough places to hide. In addition, i may add a powerhead if the aqua clear 70 is not enough on its own. the heater i'm looking at is the hagen tronics 100 watt. you think i'll be able to maintain 78 degrees in the 40 gal breeder?


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## PfunMo (Jul 30, 2009)

I should think it would be a good size. But then there are lots of things that factor in as well. How the room is heated/cooled, tight fitting cover or loose, how many, type and distance to the lights as well as other equipment that create heat like powerheads will all change the amount of heat the heater needs to put out. The heater running for longer periods will last longer than an oversized heater kicking on/off. 
What it gets down to is the fact that we can't really be precise so it is better to be slightly small on the heater rather than large. Cool fish are often unharmed for even a week and they can usually be treated back to health. It is much more common for heaters to stick on rather than stop heating. Hot fish die quickly! Two major reasons for that. Warmer water holds less O2 as well as ammonia becomes much more toxic as the temperature and PH go higher. 
For a room where the temp is normal around 70, a 100 watt is a good start for a 40 gallon. From there you can kind of give some thought to what other factors you have like hot lights, cold room, etc.


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## smitty (May 7, 2004)

A 100 watt heater will do okay in a 40 gallon tank. Now depending on where the tank is situated it may have to run longer.


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## Anthraxx8500 (Feb 11, 2011)

ambient room temperature will also affect how much you need.


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## a.wiatrowski (Jan 29, 2010)

Thanks for the help. Funny thing is I ordered the 100 watt on ebay. Well the seller contacted right after I ordered it to let me know he had no more 100 watt. So i'm getting the 150 instead lol


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