A Small Heater In A Big Tank Dilema

[oogaboogaman]

I was planning on breeding some fish in a tank thats around 5-7 gallons i believe.

the tank i have now is a 20 gallon tank

if i want to put the heater into the 20 gallon tank after i am done breeding what kind of effect on the water temperature would it have?
i would imagine it would still raise it just not that high. but i figure having warmer water is better even if its just a few degrees higher, right?

i have danios, platties and dwarf frogs

 

[kewskills]

I dont know the answer due to unknown heater wattage.
However it seems that generally 1 watt of power heats 1 litre of water, ie. 50 watt heater will heat a 50 litre tank.

hope this helps.

 

[waterdrop]

For your planning (and members please add to this if I'm wrong):

Heater of too few watts: The heater may not be able to sustain the correct temperature range needed by the fish if the house heating should fail. The larger the tank, the longer it would take for the temp to drop dangerously low in this situation. Having an under-wattage heater would slow but not prevent this situation. Losing electricity may lose both the house heat and the tank heater of course.

Heater of too many watts: Here the danger is that the fish could be cooked if the thermostat device were to fail - rare but possible.

Possible advantage of small fry tank heater: It might be possible for you, by having two heaters, maybe even going only slightly over the total wattage recommendation and then dividing by two to have the best of both worlds later. Two heaters in the bigger tank would provide a small safety net in case one of them failed. On the other hand, the small chance of failure is doubled by having two heaters in the first place, but these chances are very small, especially if you buy a good brand of heater.

~waterdrop~~~~

 

[AngelOfDeath]

i made the foolish mistake of putting a 50 watt into my 5.8 gall tank, it worked fine, but temperature fluctuation in the night cooked my guppy fry, not a pleasant sight to wake up to

as for small heaters, external temperature has more of a role to play becuase if the heater is ni a warm area, the small heater will work fine (in my experience)

 

[JodeeGust]

If the heater was made for a smaller tank, it will insufficiently heat the bigger tank. Since the tank you previously owned was in the 5-7 gal. range, I assume you got a 25 watt heater (those are made for up to 5 gal. tanks). I'd invest in a heater that was made for a 20 gal. tank just to be on the safe side.

 

[oogaboogaman]

thanks guys.

i know that it wouldnt heat a larger tank sufficently but was more curious of how much it would heat a larger tank. the fish in the 20 gallon tank have never had a heater in the tank before and they havent had any problems at all. I was just more curious if putting a two small of a heater in a tank that never has had a heater would be pointless or even bad.