What Size Heater ?

[Aqua Tom]

Get the biggest you can for your tank, the difference between a 150w & a 200w is about a £.


why not?

 

[KittyKat]

Get the biggest you can for your tank, the difference between a 150w & a 200w is about a £.


why not?

The whole argument on the first page, for example. A bigger heater can be the difference between frying your fish in an hour and frying them in a day.. even when I am away, I have someone check the equipment every day.

 

[Aqua Tom]

Get the biggest you can for your tank, the difference between a 150w & a 200w is about a £.


why not?

The whole argument on the first page, for example. A bigger heater can be the difference between frying your fish in an hour and frying them in a day.. even when I am away, I have someone check the equipment every day.

In which case you have nothing to worry about, so get a biggun.

 

[JoshuaA]

Get the biggest you can for your tank, the difference between a 150w & a 200w is about a £.


why not?

The whole argument on the first page, for example. A bigger heater can be the difference between frying your fish in an hour and frying them in a day.. even when I am away, I have someone check the equipment every day.

In which case you have nothing to worry about, so get a biggun.

Why get the biggest for your tank? It's not about money it's about effectiveness and efficiency, I tried to run a 75w on my 40l tank and it constantly kept bumping the temperature over by 2 degrees and then had to cool down and as soon as it hit 26 it turned back on and up to 28. It just couldn't keep it stable and that was rated for my 40l tank.

The checking it every day doesn't work if they fell ill so if they are worried a smaller one and less powerful should be more ideal for them.

 

[OldMan47]

If your room is within 10 to 15F of the desired water temperature, a good rule of thumb is about 5 watts per gallon. That would mean a 200W heater in your 40 gallon tank. The next thing you need to examine is whether or not you have a room that is warm enough that you don't need a larger heater. Another option, you see it all the time in pet shops, is to heat the room, because that is far cheaper than using an electric heater on lots of individual tanks. In my own case, many of my fish do fine at temperatures that I find comfortable for me. That means they do not get a heater, but the true tropicals do need one.

 

[KittyKat]

Get the biggest you can for your tank, the difference between a 150w & a 200w is about a £.


why not?

The whole argument on the first page, for example. A bigger heater can be the difference between frying your fish in an hour and frying them in a day.. even when I am away, I have someone check the equipment every day.

In which case you have nothing to worry about, so get a biggun.

Yes, yes there is something to worry about because there is no-one there check it every hour: if it is powerful enough to raise the temperature above 30°C in 1-2 hours, the fish will probably be dead if the next check is in 12+ hours.

 

[FreedomFighter]

Well well.. What a caffufle is going on in here.

I can see both sides of the argument. And you know what that says to me? It says it doesn't really make much difference whether you have a 200w or a 300w.

Except, as pointed out, that using a 300w allows you to upgrade the tank at some point without the expense of a new heater. The same goes for over filtration.

Also, I can see what the biffster is saying. And I agree that the 300w will likely heat the tank more efficiently. But the price difference would hardly be worth noting.

I have 3 heaters that will likely be fried by the end of winter. Tank temp is set to 26c, room temp in the region of 3-4c

EDIT

Kittykat your argument about a heater going haywire and frying a fish has nothing to go on. a 200w heater that malfunctions will fry a fish just as well as a 300w heater. The max temperature achieved may be lower, but it will still be high enough to fry the fish. Therefore the argument is invalid.

Now if you were running 2x 100w heaters, and one goes haywire in a 40gal, it'd raise the heat to an uncomfortable level, but it would be less likely to fry the fish in 12 hours.

 

[gunman]

Except, as pointed out, that using a 300w allows you to upgrade the tank at some point without the expense of a new heater. The same goes for over filtration.

Yes, and when you do upgrade, you're left with a tank with no heating or filtration which you can neither use nor sell becuase it is 'incomplete' .

Sorry, just being awkward!

As usual I think things are being over thought and over complicated, basic physics, to raise a defined quantity of water a defined temperature will use a certain amount of energy. Is the definition of a calorie not the amount of energy required to raise the temp of 1ml of water by 1 degree?

It isn't the same as overfiltering because the more filtration the better, the more heat........ Not really better is it?

BTW, I kept a 40G tank at a steady 27 degrees with a 50w heater for nearly 2 weeks when I was stuck! OK, it was on all the time, but a 50w heater on all the time will use the same electric (KWh) as a 200w on 25% of the time.More likely to burn out though.

 

[N0body Of The Goat]

Except, as pointed out, that using a 300w allows you to upgrade the tank at some point without the expense of a new heater. The same goes for over filtration.

Yes, and when you do upgrade, you're left with a tank with no heating or filtration which you can neither use nor sell becuase it is 'incomplete'

.

Sorry, just being awkward!

I will raise the level of being awkward... After upgrading the old tank is either kept in storage as a QT, or is sold on as a "barebones" tank, so the initial purchase of an "overkill" filter and heater is not needed for the old tank!

 

[JoshuaA]

Sorry, just being awkward!
Is the definition of a calorie not the amount of energy required to raise the temp of 1ml of water by 1 degree?

Well if you wanted to be awkward so will I!


I believe that, that assumes the system heating the water is at sea level otherwise the energy required is different as specific heat capacity changes also at different altitudes. Hence why you can boil water at like 70c on everest. So I think you get more bang for your buck

Anyway I agree, bigger isn't always better and the same applies when it comes to heaters.

Sorry, just being awkward!

^ see what I did there? :

 

[OldMan47]

You are completely off the deep end with that last statement JoshuaA. Water boils at lower temperatures when the pressure is reduced, which is why the heat needed to boil varies with elevation above sea level. Water will even boil at room temperature if the pressure is low enough. It is a classic classroom demonstration in a physics class. A water sample from the tap is placed in a bell jar and the pressure is reduced using a vacuum pump until the water boils and finally freezes into ice due to the heat lost through boiling. (Boiling removes heat from the liquid left behind.)

The heat required to raise a pound of water 1 degree F is exactly 1 BTU at only one particular water density and one particular temperature but the definition works fairly well over a wide range of temperatures and atmospheric pressures. (I use BTUs rather than calories because it is a unit I am more familiar with, not because it is a different concept.) Heat is heat and balancing heat losses, through the glass, to heat gains, from the heater, is what determines the heat input actually needed to maintain a constant temperature. Once you have achieved that balance, the temperature will never move no matter how long you allow the situation to go on.

Unless you know the shape of the tank, whether or not it is covered to prevent evaporation, the desired tank temperature, the room temperature, the air circulation patterns in the room and the thermal conductivity of the tank itself, you cannot begin to estimate the heat needed to maintain a tank's temperature mathematically. That leaves us to use standards or thumb rules to guess at the right size heater for a tank. We always estimate slightly larger heaters using that kind of guidance so that the heater can actually raise the temperature somewhat and can cycle on and off to hold a constant temperature.

FreedomFighter, the premise that any size heater will eventually overheat a tank to the point of killing fish is simply wrong. The balance between tank temperature and room temperature and the effect of raising the water temperature in the tank means that any combination of heater and tank will reach an equilibrium temperature at some point even if the heater never switches off. If that temperature is within the tolerances of your fish, no fish will be lost. An oversized heater can more readily push a tank to a temperature where that temperature will be too high for any fish. A right sized heater, as far as we can estimate it, is a good idea and achieving that size with two separate half sized heaters provides even more insurance against ever overheating the fish. Heaters do indeed stick on and most experienced fish keepers have had it happen to them at least once.

 

[JoshuaA]

You are completely off the deep end with that last statement JoshuaA. Water boils at lower temperatures when the pressure is reduced, which is why the heat needed to boil varies with elevation above sea level. Water will even boil at room temperature if the pressure is low enough. It is a classic classroom demonstration in a physics class. A water sample from the tap is placed in a bell jar and the pressure is reduced using a vacuum pump until the water boils and finally freezes into ice due to the heat lost through boiling. (Boiling removes heat from the liquid left behind.)

Water requiring less energy at lower pressures to be heated is what I said. Specific heat capacity isn't always constant, though when the pressure reduces why does it boil at a lower temperature? It boils because the required boiling point is lower as forces acting upon the water are lower. You will also find that the energy required to heat the water up by 1degree is lower at different pressures as the specific heat capacity has variables.

I don't know what part I was "Completely off" on, I may have put it across slightly awkwardly but I know exactly what I meant. The post was generally about putting energy into a fish tank via a heater, specific heat capacity was shown to say that it is the same amount of energy required to heat the tank to a set temperature whatever heater you use since we don't have our tanks strapped to the back of a sherpa. Pressure was commented on because it plays a part in specific heat capacity as it is most definitely not constant, as well as giving a example of a situation where energy required to heat water is lower, though I didn't state the boiling point is lower and for those who jumped to soon to realise I appologise.

This is getting quite far off topic and I still stand by my statement that bigger is not always better for a heater. As from what we have just discussed we should know the same amount of energy is required to raise(maintain) the temperature of water. Hence why we find you can keep very large tanks at a stable temperature on relatively small heaters and probably* using the same amount of energy. Hey, at least these are quite efficient at their jobs unlike any other device not designed to produce useful heat.

 

[Liam50]

i would get the 200w simply because its smaller and will take up less room in your tank. I mean i know watching heaters is interesting but i would rather put some more ornaments in or more plants. But thats just me. Also for the record a 300w would be way over kill i have a jager 300w on my 400l and i have it 22c setting but it heats the water to 27.