Heater Size For 190

ElectricBlueCrawfish1

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So I have a heater, I don't know what size it is and it is going in a 190 so I was wondering what size and that stuff, I can do a picture.

Also we have a 90gal sump
 
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nikm128

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According to the aqueon heater chart, their 300w can raise up to 90g up to 15 degrees warmer than room temp, so if you get two of those that leaves an unheated 10g if you want to raise the tank 10 degrees above room temp. If you need a really warm tank, I'd do 2 300w and 1 50-75w, if you don't need to warm it that much 2 300w should do the job
 

Cichlidude

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According to the aqueon heater chart, their 300w can raise up to 90g up to 15 degrees warmer than room temp, so if you get two of those that leaves an unheated 10g if you want to raise the tank 10 degrees above room temp. If you need a really warm tank, I'd do 2 300w and 1 50-75w, if you don't need to warm it that much 2 300w should do the job
If one 300 watt will do the job, the second one is for redundancy and temperature stability. The 75 will will do nothing. Remember heaters are not additive.
 

nikm128

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I don't quite follow that. If one 300w is rated for 90g, then shouldn't 2 heat 180g leaving an extra 10g?
 

Cichlidude

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I don't quite follow that. If one 300w is rated for 90g, then shouldn't 2 heat 180g leaving an extra 10g?
Uhhh... no. That's like saying 2 cars are faster than one.

Let's assume the temp in the room is 45 degrees. And one heater of 300 watts can only bring the temperature up to 60 degrees maximum. That's your 15 degree rise.

So that one heater keeps the water at 60 degrees. Now you add the exact same heater to water that is already at 60 degrees knowing that the heater can only get the water to 60 degrees. So that new heater can not heat any more at all because it is already at is 60 degrees temperature.

However two heaters will warm the water faster and keep the temperature stable. If one fails, the other one still works. Talking thermodynamics here. Electrically they will consume 600 watts but will not heat 600 watts thermally, only 300.

So you need to get one heater for what you need.

This has already been explained in multiple threads on this forum.
 
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nikm128

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Ok, I think I got it now. Does that also mean the only reason for multiple heaters would be for consistency? As in 1 heater probably wouldn't evenly heat all 4 feet of a 4 foot tank?
 

Cichlidude

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Ok, I think I got it now. Does that also mean the only reason for multiple heaters would be for consistency? As in 1 heater probably wouldn't evenly heat all 4 feet of a 4 foot tank?
Yes, that's what I mean for stability across your tank. Placing the heaters at difference ends of the tank and having good water movement is a must in that situation. For redundancy if one fails the other keeps the tank at your temperature (or at least that one half).
 

Cichlidude

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OK, now for the real world. Finding 2 of the exact same heaters that work identical? Well not really. One may heat to 5 degrees more than the other, happens a lot.

So now you have one heater that works to say 72 degrees and that's all it goes too. No further. Put in a second one of the exact same type and it runs 5 degrees higher so now the water goes to 77 degrees.

Well... look at that! Two heaters will raise the temperature!! But only one heater is doing the job, but you don't know that.

What happens if the second heater runs 5 degrees lower? Temperature says the same.

And now you know the rest of the story... ;-).
 

wodesorel

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Heaters do have a cumulative effect, they are able to raise a maximum of X degrees above current temp by maxing out their wattage. (X being unique for each heater, usually around 15 degrees.)

This is why putting the same heater on a 50-degree tank would raise it to 75, but on a 70-degree tank it would get it to 85. On the first tank it would run continuously, but on the second it would cycle on and off to keep it steady.

Having two heaters in the same tank will increase the heat by the total watts combined, because both will run in tandem until the desired temperature is reached. One may kick on before the other because of tiny differences in the built-in thermostat, but since it won't be strong enough to heat the entire water volume enough to where it would cycle off again, the second will kick in once the water cools a bit to trigger it, and both will heat together until the desired temperature is reached and then they'll kick off again.
 

nikm128

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Heaters do have a cumulative effect, they are able to raise a maximum of X degrees above current temp by maxing out their wattage. (X being unique for each heater, usually around 15 degrees.)

This is why putting the same heater on a 50-degree tank would raise it to 75, but on a 70-degree tank it would get it to 85. On the first tank it would run continuously, but on the second it would cycle on and off to keep it steady.

Having two heaters in the same tank will increase the heat by the total watts combined, because both will run in tandem until the desired temperature is reached. One may kick on before the other because of tiny differences in the built-in thermostat, but since it won't be strong enough to heat the entire water volume enough to where it would cycle off again, the second will kick in once the water cools a bit to trigger it, and both will heat together until the desired temperature is reached and then they'll kick off again.
If you have two heaters set at 80, they will not raise the tank to 160, just 80. 1 heater will have to be on a little bit more, but the amount of heaters doesn't change the temp the water can get, just how hard each one has to work
 

wodesorel

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Right, they have built in thermostats so they stop at the set temp without going over. It's when a heater is maxed out on power (watts) and still can't reach that set temp that an extra heater (or several depending on the size of the tank and the temperature of the room) is needed.
 

Wraithen

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If you have two heaters set at 80, they will not raise the tank to 160, just 80. 1 heater will have to be on a little bit more, but the amount of heaters doesn't change the temp the water can get, just how hard each one has to work
I see what you are saying, but they dont make a lot of 1000w aquarium heaters, so the op needs to run multiples on their system to achieve the desired temp.

Op, I would run 3 300w heaters. You can put them all in the sump, all in the tank, or any combination you choose. Whatever you decide, I recommend a digital setup with readouts for both set temp and current temp. This will help you keep them consistent in case the internal thermostats are off a bit. Im currently using aquatops and love them. I hate any heater with a dial as they seem to be difficult to dial in, and they dont have accurate thermostats. My 200w is like that. I have to set it at 79ish to get 78 degrees. I never have that problem with the digital ones and adjusting is as easy as pushing a button instead of adjusting a heavy dial.
 

nikm128

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That is kind of what I recommend originally...minus putting them in the sump since I'm not familiar with those filters at all
 

ryanr

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Hi,
I generally work on about 1W per Litre, or 3-4W per Gallon. Tends to be a good starting level. You may want to go higher if your ambient and target temps are drastically opposite, or less if they are closer.

I ran two 150W Eheim heaters on my 86G (66 display, plus sump) Reef quite successfully.

The Eheims can be calibrated, and you can set the temperature, I had one set a little lower than the other, as a "help me out" heater. All the equipment and lighting helped maintain heat anyway. If the primary was struggling, the secondary would kick in to help out (mainly cold winter nights), but for the most part, only one was ever active. Both heaters were in the sump.

Just a different approach I thought I'd share.
 

Cichlidude

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A member is going through this exact scenario right now using PRESET 78 degree heaters.

Heater Issues

She has one (1) 200 watt heater for 38 gallon tank. It did not get to her desired temperature of 78 degrees so she bought a second identical heater and put in in her tank and she wonders why the temperature is the same and will not go any higher.

A single 200 watt heaters will heat a 38 gallon tank with ease (assuming and ambient temperature of 60 degrees) . But now she has 400 watts!!! OMG it doesn't heat any higher! That's because the heaters are stuck and can go no higher than 74 degrees.

If the ambient temperature is lower like 40-50 degrees, then a 200 watt heater may not heat the tank to 78 degrees and that is her problem. But if the ambient (room) temperature is like 60 or higher the heaters are most likely defective.

@nikm128 understands. Great.

You can't have two pots of 150 degree water and add the two together to get 300 degree water right? Stays at 150 degrees. Otherwise you have solved the energy crisis by creating more energy than inputted as water boils at 212 degrees, 300 would turn to steam.

I asked this of Eheim Jeager to verify my math a while ago...

*****
Hello,

I have a question about your aquarium heaters.

If I have a heater that is only capable of heating the water to 60
degrees max, would adding a second identical wattage heater raise that
temperature more?

I think not. If one heater can only heat to 60 degrees, the second
heater added can only heat to 60 degrees also. The water is already at
the temperature so how can it raise the temperature?

The reason I ask is that folks say to add a 2nd identical heater to
raise the temperature more.

Thank you in advance.

Regards,

******* Eheims answer ****

Hi the heaters ability to heat the water will also be based on ambient room temperature. In general a heater will heat the water up 10'F above the ambient room temperature. The set temperature on any given heater will heat within +/- 1'F based on assumed near perfect accuracy, adding additional heaters will help stabilize the temperature of the water but it will not increase the overall ability to heat a given volume of water.


Eheim Support | info@eheimsupport.com

*****

Done.
 
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