I currently have 500w (a 300w & 200w) heating my 540L tank (probably more like 500L of water). I need a heater for my new 200L so was thinking about snaking the 200w out of my main tank. Will the 300w handle the job on it's own? The tank is in our lounge which is always reasonably warm as it's our main living space. Room temp would be 20-23 most days & nights.

Assuming the following:

1500x600x600mm tank (uninsulated)

Tank temperature: 27degrees

Room temperature: 20 degrees

You will need a minimum of 212 Watts (continously heating 24/7) to sustain the 27 degrees.

So, yes 300w will do. (for those circumstances... if temp drops during winter nights you might be in trouble)

HTH

It'd probably be ok at the moment but id keep an eye on it. You wouldnt want it going non stop. Like Hovmoller says you may need another to help it in winter.

OK thanks for that. Probably would survive the summer but will need to add a heater for the winter. At least I can get both tanks up and going immediately. Thanks again

a 300W jager will, other brands probably won't.

a 300W jager will, other brands probably won't.

+1

Jager are good quality but surely 300w is 300w.

Jager are good quality but surely 300w is 300w.

i don't know the science of it but it is rated for a 1000L tank. It keeps my 400L tank at a constant temp at the coldest parts of winter in my garage so i'm confident a 500L tank will be the same. Its not always how big it is, it's how you use it that counts

Jager are good quality but surely 300w is 300w.

300W is still 300W of heating, I just wonder if the jager heats more efficiently because it has a longer heater element?

300W is still 300W of heating, I just wonder if the jager heats more efficiently because it has a longer heater element?

or maybe the thermostat is so good that it turns on a lot sooner than other brands so it is easier to maintain the temp. not sure but the reality is it keeps the tank at the set temp or very near it constantly, other heaters i've owned would have 2 or 3 degree drops regularly on tanks that were only 75% of the 1W/L theory.

I think that will be more to do with the hysteresis of the thermostat than the rating of the heating element.

I guess it is always possible that a poor quality heater may be claimed to be 300 watts when it is not.

I think that will be more to do with the hysteresis of the thermostat than the rating of the heating element.

I guess it is always possible that a poor quality heater may be claimed to be 300 watts when it is not.

Yeah, assuming it's actually drawing 300 watts then it will be heating 300 watts. But if something like the element is heating the body of the heater and making the thermostat read high it's possible it could switch off early until it cools down and reads accurately again.

Seems it wouldn't be too hard to test. Throw one of each heater in a cold tank for 2 hours, put a watt meter on them. Both should peak at 300 wattsish and use .6 kw/hours.

i don't know the science of it but it is rated for a 1000L tank. It keeps my 400L tank at a constant temp at the coldest parts of winter in my garage so i'm confident a 500L tank will be the same. Its not always how big it is, it's how you use it that counts

I have bought a Jager 300w for a 430lt tank. Must say I set the temp and it has not moved. Normally I would watch my tanks drop a bit overnight but not this tank.

They are rated for a 600-1000lt tank.

They pickup a temperature change of +/-0.5C

i have found they do exactly what they state they will, don't know how but they do it.

It comes down to simple math: Click

Sure you can figure out what it all means - even if it's in German

JaSa

There is even an english one on this site: http://www.fnzas.org.nz/fishroom/viewtopic.php?f=3&t=48031

It comes down to simple math: Click

Sure you can figure out what it all means - even if it's in German

JaSa

The math involved in calculating aquarium heatloss is anything but simple..

The German site you linked to is far far too conservative.. e.g. a 400L tank, room temp 20 tank temp 27.. it says I need 350w heating... that is BS and we all know it..

Besides it doesn't take into consideration the shape of the tank which determines surface area (all 6 sides) where heat is lost.

The math involved in calculating aquarium heatloss is anything but simple..

The German site you linked to is far far too conservative.. e.g. a 400L tank, room temp 20 tank temp 27.. it says I need 350w heating... that is BS and we all know it..

Yup, I'd say doesn't need anywhere near 350w. I've had a 150 watt heater in my 440L tank and that varied a degree or two over winter in a room that gets under 20. 350 should be way more than enough.

Couldn't find any information about the shape of the tank nor the surface areas in this thread so I thought it is a standard tank - and for that's what the calculator is prob. designed for. But looks like hovmoller got some more detailed informations about the 540l tank mentioned by the topic starter

But anyway - I always used two heaters in my bigger tanks. Gives you a bit of security in case one goes down and the heat is spread more evenly if you don't have a big water movement. Let us know how you go during winter, will you?

Cheers,

JaSa

Assuming the following:

1500x600x600mm tank (uninsulated)

Tank temperature: 27degrees

Room temperature: 20 degrees

You will need a minimum of 212 Watts (continously heating 24/7) to sustain the 27 degrees.

So, yes 300w will do. (for those circumstances... if temp drops during winter nights you might be in trouble)

HTH

i don't agree with the "continuously heating" at all. I have had 200L tanks with 200W of heat and they certainly were never on 24/7, probably not even 12/7. calculations are based on our knowledge on something so can be exact or a complete guess if we don't understand all factors.

But anyway - I always used two heaters in my bigger tanks. Gives you a bit of security in case one goes down and the heat is spread more evenly if you don't have a big water movement. Let us know how you go during winter, will you?

Cheers,

JaSa

there has been many opinions on this over the years, i to started off with the attitude of a heater at each end etc but have proved myself to be over thinking it as I now have a 2.0m tank with a single jager 300W in the middle at it is fine year round even though it is in my garage which has been lined to create a rumpus. It get s very near outside temps in there as it has two strips of clearlite roofing and has no insulation. What i have learnt is that large bodies of water seem to hold their temp longer, 30% water changes don't take the temp down in this tank as much as the smaller ones i have found.

i don't agree with the "continuously heating" at all. I have had 200L tanks with 200W of heat and they certainly were never on 24/7, probably not even 12/7. calculations are based on our knowledge on something so can be exact or a complete guess if we don't understand all factors.

Not sure if you misunderstood the "continuously heating". This is what I meant:

The calculation is purely theoretical assuming a tank with the above dimensions full of water. To sustain a temperture difference of 7 degrees you will need 212 watts of energy to go into the tank continuously. It does not take into consideration any energy gained from pumps, lights, etc.

Also I'm not sure why you compare with a 200 L tank? the tank in question here is a 540L tank.