Heater for a small tank, is anything too big?
- Thread starter brillow
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tyspot1000
Aquarium Advice Addict
The risk could be making the temp too high, I wouldnt recommend getting anything bigger than what it is rated for 
azure bones
Aquarium Advice Freak
Should be fine aslong as its adjustable wouldn't try in a stocked tank I have the one out of my old tank rated for a 55 gal in my 15 with it on the second to lowest setting and it keeps my tank at the correct temp but if its non adjustable I'd say no and if ur tank is already stocked I wouldn't risk it some lfs might trade for a smaller one or give a discount mine used too but stopped selling used recently
dkpate
Aquarium Advice Addict
I always get a bigger heater than is recommended. For my 10 gallons, I have a heater rated for 15-20 gallons.
I agree, there is no harm with having a larger heater unless the tank is really small. I have 50W heaters in my 10's. All it will do it take less time to heat the water.
The risk of the heater malfunctioning and overheating the tank exists whether the heater is more powerful than needed or not. It's an urban legend that a powerful heater will overheat the tank.
dkpate
Aquarium Advice Addict
+1. If the tank is smaller than 5 gallons, I would go with a heater rated 1-5 gallons though, nothing bigger.
mgamer20o0
Aquarium Advice Addict
you want a 3-5w per gallon or there about for heaters. it depends on the temp in the room. the only problem is using too big of heater it will turn off and on more often and higher chance of it to fail sooner.
Why would turning on and off cause it to fail sooner?? I could say something similar about a less powerful heater - it'll be running more often, therefor it's more likely to break. I've heard all sorts of "reasons", none of which have ever been substantiated. IMO and E, it's just people perpetuating a myth. It's so pervasive that I've actually seen people recommend getting a heater that is too small for the tank, that way it won't cook the fish if it breaks. How ridiculous.
BigJim
Aquarium Advice Addict
Turning electronics off and on constantly wear them out sooner than turning them on and leaving them for a reasonable amount of time because they're rarely operating in steady state mode. The transient mode is more damaging.
That said, I don't know how long it takes a heater to get to steady state. I have both undersized and oversized heaters in my tanks. I've got a 100W in a 29g and a 300W in a 40g. Both do the job.
That said, I don't know how long it takes a heater to get to steady state. I have both undersized and oversized heaters in my tanks. I've got a 100W in a 29g and a 300W in a 40g. Both do the job.
Tim Wheatley
Aquarium Advice Addict
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With that said, Google released stats on hard drives in their storage sometime last year and it made for some interesting reading. They had drives which were ten years old going strong, while others had lasted a month. Their stats (because being google they kept records, of course) said that if electronics were going to fail, they failed almost immediately. If they lasted the first 3 months the chances were they would last many years.
If the heater has a temp setting on it, then there is only one difference, and that is how much capable the heater is of heating the surrounding water. The higher the wattage, the quicker and more effectiveness of the heater. Putting a 300w in a 10 gallon won't have any detrimental effect, infact the stability of your tanks temp will be greater. With a lesser wattage you could have variations in temp caused by the increased amount of time taken by the heater to heat the water.
Whether it is on and off for a more or lesser amount of time SHOULD have nothing to do with it. I'd much rather have a heater that successfully goes on and off a hundred times a day than one which has only been tested a few times and might fail on any of them.
If the heater has a temp setting on it, then there is only one difference, and that is how much capable the heater is of heating the surrounding water. The higher the wattage, the quicker and more effectiveness of the heater. Putting a 300w in a 10 gallon won't have any detrimental effect, infact the stability of your tanks temp will be greater. With a lesser wattage you could have variations in temp caused by the increased amount of time taken by the heater to heat the water.
Whether it is on and off for a more or lesser amount of time SHOULD have nothing to do with it. I'd much rather have a heater that successfully goes on and off a hundred times a day than one which has only been tested a few times and might fail on any of them.
I would think electronics that are designed to go on and off, such as a heater, would be able to bypass such issues.
mgamer20o0
Aquarium Advice Addict
ever notice how people say better to get two smaller heaters as well. any device is going to fail at some point. having a 300w heater in a 10 gallon tank when it stops working right will stop heating the tank or fry them.
you ever hear how people say leave the comps on dont ever turn them off or dont turn it off and on all the time?
having a heat turn on and off in a few secs will be better then one that stays on few a little while then turns off.
Tim Wheatley
Aquarium Advice Addict
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I have heard that, but working in the industry I don't believe it.
Google never turn their storage off, and they had drives which failed at varying times, that proves in itself that leaving them on caused random results. Turning them on and off would have done the very same.
Google never turn their storage off, and they had drives which failed at varying times, that proves in itself that leaving them on caused random results. Turning them on and off would have done the very same.
aprilp
Aquarium Advice Apprentice
ugh, heaters! my heater is the only thing in my tank giving me a problem. My poor fish either end up at 72 or 82. I'd like to keep them around 76-78ish but when I adjust the heater even in just tiny little movements it does too much. Does that mean its too small or too big for the tank? Confusing!
Here's an example. In the evening tank is 72ish, too cold IMO. I bump it up maybe three little tiny movements. By the next morning, the tank is 82! Bump it down maybe two little tiny movements. By the next evening, tank is 72-74 again. And so on and so forth. Continuously. Poor fish! I wish they made (or if they do, that I had to money to purchase) a heater that you can set the actual temperature to what you want the tank to be and be done with it. (If they do make it, how much does it usually cost?)
Totally off topic, but the other day I went to a LFS(chain) and bought two platys and I had to explain to the fish person how to tell if a livebearer is a male or female. She had no idea!!! (nor did another of their fish ppl) Luckily, I got a survey on my receipt and when they got to the part about things they can improve, I made sure to say, "Train your fish ppl so they at least know how to tell the sex of a fish and a little bit about running a tank!!
Here's an example. In the evening tank is 72ish, too cold IMO. I bump it up maybe three little tiny movements. By the next morning, the tank is 82! Bump it down maybe two little tiny movements. By the next evening, tank is 72-74 again. And so on and so forth. Continuously. Poor fish! I wish they made (or if they do, that I had to money to purchase) a heater that you can set the actual temperature to what you want the tank to be and be done with it. (If they do make it, how much does it usually cost?)
Totally off topic, but the other day I went to a LFS(chain) and bought two platys and I had to explain to the fish person how to tell if a livebearer is a male or female. She had no idea!!! (nor did another of their fish ppl) Luckily, I got a survey on my receipt and when they got to the part about things they can improve, I made sure to say, "Train your fish ppl so they at least know how to tell the sex of a fish and a little bit about running a tank!!
Tim Wheatley
Aquarium Advice Addict
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No, it probably means it is a bad heater. But if you're the one adjusting it all the time then that's probably not the case.
Why would you keep adjusting it? A stable temp is more important than the perfectly recommended one I would think. But even saying that... In the wild rain makes rivers a different temp anyway for short periods.
Why would you keep adjusting it? A stable temp is more important than the perfectly recommended one I would think. But even saying that... In the wild rain makes rivers a different temp anyway for short periods.
jsoong
Aquarium Advice Addict
The only worry about using a big heater in a small tank is when the heater fail in the ON position. <ie the heater won't turn off at set point.> A small heater won't raise the temp too much, but a big heater would cook your fish.
Tim Wheatley
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This is incorrect.
The larger heater simply has more power, what this power does is alters speed, not the actual temperature. A small heater can go to just as high a temperature as a large one, it would just take longer to do it.
The larger heater simply has more power, what this power does is alters speed, not the actual temperature. A small heater can go to just as high a temperature as a large one, it would just take longer to do it.
aprilp
Aquarium Advice Apprentice
I dont know....I guess I just wanted it to be in the middle so that everyone was happy. Some of the stuff you read about mollies is that they dont like the water too cool and then the other fish dont like the water too hot, so I thought somewhere in the middle would be nice for them all. Sometimes I have been able to get it a decent temp and keep it for a couple days but then it changes and messes me up all over again. I think maybe its the fact that its been really cold here and then not so cold and then really cold, etc. Which means also a fluctuation in how often the heater in the house turns on etc. It just seems to vary alot of the time and I just didnt think that leaving it as low as 72 or as high as 82 (and sometimes 84!) was good.
Tim Wheatley
Aquarium Advice Addict
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72 might be a little cool for some. You can keep trying to get it to 76-78 or so if you want to. 82 is higher than I'd probably go unless I was trying to deal with a parasite. Maybe you could look for another heater when you are able to with a better adjustment knob on it.
April, look into marineland or another brand like it. They sell nice heaters for fairly cheap. Best thing about Marineland heaters (at least mine) is it has a lifetime warranty and it was 35 bucks for a 200 watt heater. THAT WORKS!
