# Aqueon Pro 250W Heater for a 125G?



## jnick (Aug 17, 2011)

Does that sound about right? Would a 250W Aqueon Pro heater be sufficient enough to heat a 125G aquarium? It's using a Fluval FX5 with a custom 4ft spray bar. It will also be using two powerheads in the very near future.

The room temp is usually stable around 66-68*F. I'd be keeping the tank around 79-80*F normally and will raise it as close to 85*F for cycling.

I've had awesome results with my Aqueon pro in my 55G and would love to stick with that series for my 125G.

Thanks!


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## prov356 (Sep 20, 2006)

I would start with a 250w, yes. A 300w may be too much.


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## Mike_G (Nov 8, 2011)

250W is the highest they go- I think that'd work okay though.

2 150W units might be a better option


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## 13razorbackfan (Sep 28, 2011)

I have a 250w in my 75g and it keeps temp perfect 78. I have a 150w in my 30g which also keep temp at perfect 78. I keep my house cold so I went a bit higher in my wattage.


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## jd lover (Mar 11, 2011)

i have 2 200 in my 125 and i cant get the tank pass 87 =/


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## 13razorbackfan (Sep 28, 2011)

jd lover said:


> i have 2 200 in my 125 and i cant get the tank pass 87 =/


I can't get either of mine past 86. Mine shut off at 86 right on the nose.


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## jnick (Aug 17, 2011)

I installed the heater around 8pm last night and set the dial to 84*F. It's now about 7:30am, nearly 12 hours later) and the tank is at 75*F, with the light still red. Should it normally take that long (room temp is 68)? Or do you think I need to pick up a second heater? Or possibly two 150W and return the 250w?

Thanks!


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## prov356 (Sep 20, 2006)

Don't make the mistake of many, fearing that you don't have enough 'power'. Too much power is what you should avoid. Leave it be and see what it'll do. I never run nor recommend two heaters in a tank on their own controllers. No need and can operate either erratically or inefficiently. If you need 300w, get a 300 watt heater, or put two heaters on a single controller, but doesn't make sense for low wattage heaters. Give it time. What temp was the water when you first turned it on? What's the current room temp?


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## jnick (Aug 17, 2011)

When I put the heater in and turned it on, the tank's water temperature was at 66*F. The room temperature is 68*F. The tank is now at 75*F, with the red light still pumping away; still heating the water. Therefore, in a 12 hours time span, it raised the water temperature of a 125G tank 9*F.


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## Narwhal72 (Sep 26, 2006)

It's a pretty large volume of water and you are looking at a 15 degree rise above ambient. It will take a long time to get up to temperature but once it's there it should be able to maintain it (but it will run a lot which adds up the power bill).

I would add a second heater on the opposite side of the tank. This will distribute the heat better in the aquarium and give you better reliability and lower power since two heaters will not run as much as one.

Andy


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## prov356 (Sep 20, 2006)

> When I put the heater in and turned it on, the tank's water temperature was at 66*F. The room temperature is 68*F. The tank is now at 75*F, with the red light still pumping away; still heating the water. Therefore, in a 12 hours time span, it raised the water temperature of a 125G tank 9*F.


I wouldn't rush to any judgment yet. That rise is normal. I get 2 degrees per hour on a storage tank with 4w per gallon. Let it go. As far as how much it will run, time will tell. Adding more wattage so it heats faster and runs less won't necessarily require less electricity, and therefore cost less to run. More watts running less can cost the same as less watts running more.

Unless a tank is woefully inadequate circulation wise, running a second heater to distribute heat better is very unnecessary. And the heat from one can result in excessive cycling by the other.


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## jnick (Aug 17, 2011)

Thanks for the information. So is the thought that *if* I need another 250W heater, I _must_ run them off of a controller to keep the fish safe? If that's the case, what controller does one recommend? Does the RKL Lite seem to fit the bill as I know I can hook up two heaters? I know Ranco controllers are good as well, however I don't know if I can hook up multiple heaters.

Thanks!


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## prov356 (Sep 20, 2006)

If you need more wattage, and you want to go with a controller, then I'd consider two 150's, not 250's. No way you need 500w for this tank.

Running them both off of one controller will allow them to work in sync instead of possibly affecting each other in unpredictable ways. It will also keep the fish safer because the high end controllers tend to be more reliable. It's the controller in the typical hobbyist heaters that fail, stick on, and kill fish by overheating the water. Not going overboard with wattage is still recommended. And they do make 300w heaters, plenty of them. No reason to get stuck on one brand. All manufacturers put out some lemons, based on the feedback here.


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## jnick (Aug 17, 2011)

Cool, thanks for the info! Do you know if the ReefKeeper Lite would do the job? It looks like it has 4 receptacles, and I would imagine I could program each receptacle as a type I see fit? IE: Outlet 1-2 = Heater/Temperature, 3 = Lights, 4-5 = Wave Make, etc?


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## Narwhal72 (Sep 26, 2006)

It will take 15,645 BTU's (4.58 kilowatt/hours) of energy to heat 125 gallons 15 degrees. Assuming perfect efficiency in the heaters it should take just over 18 hours to get the water up to temperature. Once it reaches temperature, and assuming the heater has a 1 degree differential it will take 0.3 kilowatt/hours of energy each cycle (heat up to setpoint, cool down to low end point) to maintain it.

This means that once the aquarium cools down below 1 degree of the setpoint the heater will need to run for just over an hour to get it back up to temperature.

Going to 2 150 watt heaters will get that to just about an hour. But heat distribution in a 6' tank is the key. I have seen many tanks that may have a 2-3 degree differential from one side to the other just because of poor circulation which is why having two heaters is better.

Andy


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## Mike_G (Nov 8, 2011)

Narwhal72 said:


> It's a pretty large volume of water and you are looking at a 15 degree rise above ambient. It will take a long time to get up to temperature but once it's there it should be able to maintain it (but it will run a lot which adds up the power bill).
> 
> I would add a second heater on the opposite side of the tank. This will distribute the heat better in the aquarium and give you better reliability and lower power since two heaters will not run as much as one.
> 
> Andy


Running two heaters won't save any power


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## 13razorbackfan (Sep 28, 2011)

When I had ICH in my tank I needed to crank my aqueon up to 86. It took more than half a day to get to that temp and that is a 250w in a 75g. Just give it time...

On a side note...the other day for some reason after a water change I messed up with the refill and the tank temp dropped from 78 to 74. It took almost 1 hr give or take for the tank to reach 75. It took more than 4hrs to get back to 78. That is what you want in a heater...raises temp slowly instead of powering on and off.


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## Totalimmortal363 (Jan 10, 2008)

I have an Aqueon 250 on my 125. Seems to keep the temps pretty stable, my therm is on the opposite side of the heater.


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## Narwhal72 (Sep 26, 2006)

Because of the uneven distribution of heat in an aquarium (particularly long tanks like 125's) adding two heaters will indeed reduce power consumption in many aquariums.

The reason is that if the heat is not evenly distributed in the aquarium hot and cold spots will form in the aquarium.

If you are controlling your heat by a thermometer on one side of the tank and the heater is on the other side, many people will find that they need to turn their heater up 2-4 degrees higher than the setpoint they would like on their thermometer. This forces the heater to spend more energy getting the water around the heater warmer so that there is a gradient from warm to cold that matches the desired setpoint on the thermometer.

If there is a heater on each side of the aquarium, or the aquarium has a strong circulation pattern that minimizes hot spots, these gradients do not occur and the heaters spend less energy getting the temperature up to the setpoint.

Andy


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## mobafrontlover (May 1, 2011)

Sorry if this Is a dumb question but how do the controllers work if the heaters have I built-in cut off point? Do you have to use I special heater? Do you set the heater to the hottest point and plug it into the controller?


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## jnick (Aug 17, 2011)

Let's say you want the heater to keep your aquarium at 80*F. You set the heater to 85*F and then the controller to 80*F. When the controller's probe reads the temp at 80*F, it will cut off power to the heater.

At 5pm today, the temperature in the tank was just about 80*. By 8:30 it was at 82*, which is where it's stayed since then.


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## 13razorbackfan (Sep 28, 2011)

jnick said:


> Let's say you want the heater to keep your aquarium at 80*F. You set the heater to 85*F and then the controller to 80*F. When the controller's probe reads the temp at 80*F, it will cut off power to the heater.
> 
> At 5pm today, the temperature in the tank was just about 80*. By 8:30 it was at 82*, which is where it's stayed since then.


Good to hear!!!


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## mobafrontlover (May 1, 2011)

O ok cool thanks


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## Mike_G (Nov 8, 2011)

Narwhal72 said:


> Because of the uneven distribution of heat in an aquarium (particularly long tanks like 125's) adding two heaters will indeed reduce power consumption in many aquariums.
> 
> The reason is that if the heat is not evenly distributed in the aquarium hot and cold spots will form in the aquarium.
> 
> ...


The circulation in the tank seems like it would have to be pretty bad for that to be true, but I'll buy :thumb:


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## jnick (Aug 17, 2011)

Besides the fact that I'm running a 4ft spray bar, would I be correct in saying that due to the fact that the heater has yet to go 'green', means I have good circulation? The only time it went green was when I shut the filter off to add biomedia, due to the standing water.


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## 13razorbackfan (Sep 28, 2011)

jnick said:


> Besides the fact that I'm running a 4ft spray bar, would I be correct in saying that due to the fact that the heater has yet to go 'green', means I have good circulation? The only time it went green was when I shut the filter off to add biomedia, due to the standing water.


You should have good circulation with a FX5. You could actually add more with no issue but yes...your circulation and water movement is part of the reason it is working harder to heat. That is really better than turning off and on over and over.


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## Totalimmortal363 (Jan 10, 2008)

Just an update, I added a second glass thermometer so I have one on each end of the tank. BOTH are within one degree of eachother. NO HOT/COLD SPOTS!


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## prov356 (Sep 20, 2006)

> BOTH are within one degree of eachother.


And that could be because of thermometer variances. If someone truly has a 4 degree difference in temps from one side of a tank to the other, I"d suggest it's not a heater placement problem, but a circulation problem. Besides, water stratifies, meaning it forms horizontal layers with cooler water on the lower layers and warmer above. You'd see differences in temp top to bottom, not left to right if circulation was very low. Warm water will move across and over the cooler water even if there is no means of circulation in the tank.



> At 5pm today, the temperature in the tank was just about 80*. By 8:30 it was at 82*, which is where it's stayed since then.


Give it a bit more time. If this is truly as high as a 250 will take the tank, then I'd consider bumping up and running the same test.


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## Narwhal72 (Sep 26, 2006)

Keep in mind that most filters, spraybars, etc are usually set up along the top rear wall of the aquarium. This moves water across the top of the tank from back to front, down the front, across the bottom and back up the rear wall.

If you have a 2' spray bar setup on one side of a 6' long tank you can have 4' of space with much lower water movement. You still have the water movement as the water moves from the spray bar towards the filter intake (assuming you have the filter intake on the opposite side of the tank) but the velocity of this water is much slower as you are moving across a much larger area.

That's why it's a good idea to use a powerhead or prop pump on one end of the tank pushing down the length of the tank to improve circulation. Even arranging the spray bar to go along an end of the tank (back to front) so the water is pushed down the length can improve circulation and heat distribution dramatically.

Andy


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## Totalimmortal363 (Jan 10, 2008)

I guess I'm demonstrating that one 250W Aqueon Pro can do the job with good water circulation, which I have.


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## jnick (Aug 17, 2011)

As of 9am this morning, the tank was happily sitting at 84*F. Now for the first time, I'm seeing the light be green. I'm currently keeping an eye on the difference between how long it remains passive and how long it is active.


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## Narwhal72 (Sep 26, 2006)

Whether it can do it or not is not the question immortal. It is whether it is doing it efficiently.


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## jnick (Aug 17, 2011)

Now that I've been using the heater for a week or so, here is what I'm noticing. It will turn itself off for no more than 5 minutes at a time. At that point it will turn itself back on and begin heating the tank. Is this okay? Or am I better with two 200w?


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## 13razorbackfan (Sep 28, 2011)

Sounds ok to me...is the temp staying stable or is it swinging? If it is having a hard time keeping temp then you might get another.


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## jnick (Aug 17, 2011)

Nope, everytime i check, the temp is at 85. It just plays the on/off game quite a bit.


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## 13razorbackfan (Sep 28, 2011)

jnick said:


> Nope, everytime i check, the temp is at 85. It just plays the on/off game quite a bit.


It's fine...once you bring it back down to 78 it will not have to work as hard.


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