# Temperature issues



## Drewcifer (Mar 4, 2012)

Hey guys, I've had fish for a while but have been basically flying by the seat of my pants in terms to keeping a normal, healthy tank. Just getting into actually being serious about it and keeping a good tank (which will be transitioning into a planted tank in the very near future I hope) and I've been having issues maintaining temperature.
I've had my heater set on 75F and I notice some days the water feels relatively cool to the touch, and then the next day feels very warm, like almost as warm as I'd feel comfortable showering in. I was using 2 of those strip thermometers that you stick to the outside of the tank and they were garbage so I got an internal floating thermometer, and it reads 82F while my heater is set to 71F now. The water feels pretty cool to the touch.
I want to assume that the temperature of my room is bringing it up above whatever the heater has set it too so that accounts for the difference in heater setting vs thermometer reading. Is that the case? Is this normal?


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## Darkblade48 (Jan 28, 2008)

Indeed, the stick-on-type of thermometers are not the best for taking the temperature of the water inside the aquarium. The floating type are much better.

Did you check to make sure that the piece of cardboard inside the floating thermometer did not shift? They can sometimes do that, leading to erroneous readings. The best way to get a good one is to go to the store and look at all the thermometers and choose one that matches with the reading that most of the thermometers have.

What kind of heater are you using? If it is set to 71F, and your aquarium water is 82F (and your thermometer is correct), then I would suspect that the heater is defective (i.e. sticking on the "on" position). It is unlikely that your room is heating up the water in your aquarium that much (11F? That is about 6C, and for your aquarium to be at 82F, your heating would have to be set to at least 28C...)

I would check your thermometer first, then your heater.


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## Drewcifer (Mar 4, 2012)

The thermometer appears to be ok. The card with the readings inside seems positioned properly, just like all the pictures I can find for the same kind online.
My heater is a Hydor Theo Submersible 200 Watt. Its probably a year old or less. Is there a way to test if it is defective for sure?


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## kbn (Feb 23, 2012)

There's another factor that can raise your temperature up: light.
Is the heater on? Most of them have little LED that indicates on/off. If both your thermometers show same reading and heater (set up way below reading) is still on - just toss it away, and don't try to save $5-10, just get Eheim - they're still made in Germany.


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## Darkblade48 (Jan 28, 2008)

Drewcifer said:


> The thermometer appears to be ok. The card with the readings inside seems positioned properly, just like all the pictures I can find for the same kind online.
> My heater is a Hydor Theo Submersible 200 Watt. Its probably a year old or less. Is there a way to test if it is defective for sure?


It is impossible to tell if the cardboard inside the thermometer is placed properly if you are only comparing with pictures online...However, for time being, assuming that the thermometer is fine, then it could be your heater.

If it has an indicator light, then you can determine if it is constantly on.

As mentioned by kbn, your lighting could raise the temperature of the water as well.



kbn said:


> There's another factor that can raise your temperature up: light.
> Is the heater on? Most of them have little LED that indicates on/off. If both your thermometers show same reading and heater (set up way below reading) is still on - just toss it away, and don't try to save $5-10, just get Eheim - they're still made in Germany.


I heard that the newer Eheim made Ebojagers aren't as reliable as the older Ebojagers...


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## Drewcifer (Mar 4, 2012)

If my thermometer reads 78 right now, which it does, and I set the heater to that, it should turn itself off fairly quickly since the water is already at that temp, should it not? If so, thats how I will test it tonight.


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## BillD (Jun 5, 2006)

You can't go by the setting on the heater. Set it so it keeps the temp you want regardless of what the dial on the heater says.


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## Drewcifer (Mar 4, 2012)

Well assuming my new floating glass thermometer is in fact correct the temperature has leveled out at around 73F, which is good considering I had the heater unplugged all last night and all day today so I'm not worried if my heater is wonky and I have to ditch it. I just set the heater to 75 and I'm gonna see what that does. In the morning if the temperature looks to be well beyond that, I guess my heater is busted.

Was wondering if the positioning of the heater makes a difference, both in terms of where in the tank in relation to the filter intake or output, and how the heater is aligned (vertical/horizontal/diagonal)?


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## kbn (Feb 23, 2012)

Forget about marks and numbers on the heater, just play a bit with adjustment, check if you're able to set it the way it turns itself on below desired temp./ off -above. Or, just get the new one before you cook your fish. BTW such a changes of temperature as you described, may kill your fish too. And, overall, new heater might be cheaper than new fish.

Darkblade48: Jäger is still Jäger and still über  - my opinion


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## Drewcifer (Mar 4, 2012)

Had it set to 75, went out for a few hours, came back and thermometer reads almost 82 and its luke warm to the touch. I turned the heater to the lowest setting and not long after the light went out, so I'm guessing it does in fact read temperature and turn itself off, so I just gotta forget what numbers it has on it and play with the dial and compare to my thermometer as suggested.

How about some suggestions for a replacement heater in the near future?

Also sorry for sounding like such a noob, this was probably such a basic issue that I probably should have figured out on my own


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## Darkblade48 (Jan 28, 2008)

As mentioned, the best way is just to forget the numbers on the dial of the heater and go according to the actual temperature of the water.

On some heaters, it is possible to recalibrate, I believe.

As for a new heater, as mentioned, the Ebo Jager line is excellent. I have been using the same one for 12 years now.


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## ameekplec. (May 1, 2008)

I may have missed this, but how many gallons is your tank, and how much is the temperature difference in the room with what you want in te tank? To me it's simply sounds like your heater is probably too big for your tank - try a 100w or smaller heater and most likely you won't have such a large over shoot of the set temp.


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## Drewcifer (Mar 4, 2012)

My tank is 50g. I don't know what the temperature of my room is.


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## Lee_D (Jun 11, 2010)

I have also tried the Theo's over the last year. I bought three for my three 120g tanks and I ended up with the same issue. They work fine when you first get them but after about a year you can no longer control the temperature. It doesn't matter where you set the knob on top, they just start to over heat. And the red light is not much help. They actually think you want a temperature setting of 91F. I use a digital thermometer and it read 91 in the tank and 71 outside the tank. I can accept one failure but i had the same issue with three out of three. I have since replaced them with 200W Jagers which seem to work ok. All three tanks are now 79F +- 1F.

Lee


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## Drewcifer (Mar 4, 2012)

This morning my temp was 84! I turned the heater to the lowest setting and the light went off and I don't expect I'll touch it again. I'll let it settle at room temp and I'll look into a new heater. 
Is 200w good for 50g or should I use less do you think?

So glad my BGK is handling all this well. He's tough as nails. Hes getting a nice big helping of bloodworms when I get home!


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## Darkblade48 (Jan 28, 2008)

200W is probably more than enough for a 50 gallon aquarium. 

The wattage of heater that you choose is dependent on how much you want to raise the temperature of the water by (compared to room temperature).


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## Lee_D (Jun 11, 2010)

When I bought the Theos the guy in the store told me the rule of thumb is 4 Watts per gallon. After the Theos, I think that is overkill. I have three 50g tanks and they were fine with 100W heaters. But like Darkblade says, it depends on whether you want a warm tank or not.

Lee


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## pat3612 (Jan 29, 2008)

The problem with heaters is this what I did not even think until I changed to salt water you need movement . Filters are not enough to move the water. I have seen a big change since I added a power heads to my fresh water tanks, my fry seem to grow faster and my temp is always right on.


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## Drewcifer (Mar 4, 2012)

100w Jager in. Temp stable at 76.


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## kbn (Feb 23, 2012)

Wow! It took you only 8 days! Bravo! Lucky BGK - didn't get cooked.


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## solarz (Aug 31, 2010)

kbn said:


> Wow! It took you only 8 days! Bravo! Lucky BGK - didn't get cooked.


82F isn't too bad, i get that for weeks during the summer


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## Drewcifer (Mar 4, 2012)

My old heater wasn't on all that time. I took it out and let the tank match the room temp.


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## Mlevi (Jan 28, 2012)

*Temperature Woes...*

I found out the hard way....
Should have read this thread beforehand instead of afters...sigh!

This morning, the temp in my 15 Gallon tank was off the charts, and my fish were floating on the top. Lost my quad of breeding guppies, and about 20 or so month old fry 

The heater I was using, was a 150 Watt 12" 'supreme' that has worked for me since I got the tank. I never had any temp issues through 3 months of use, which I rigidly monitored everyday. Was fine last night, and then overnight just shot up. Either the thermostat gave up, or I somehow jiggled the temp knob (these heaters have no discernible markings on the top - old school). I was so disgusted I just smashed the heater...didn't even think about finding out what the cause was.

I replaced it with a new 50 watt spare that I had bought from BA (one o' those 10 dollar deals), and will pick a more reputable brand / newer unit.

Now back to cycling my tank, and carrying the guilt of killing my fish


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## mkblitz (Oct 12, 2011)

I have a ghetto TopFin 300w heater (came with the tank) and it would keep heating until 30deg C on the LOW setting. It's probably close to 10 years old but I finally set it on a timer and tweaked it eg. 3 hours on, 3 hours off, and so on for the whole day. That way it keeps the temperature between 24-26 degrees at all times.

Just another ghetto solution for those who do this hobby on the cheap 
(Disclosure: yes all my fish are still alive)


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## deragoku (Apr 16, 2012)

As you describe this temperature change may kill your fish. Overall, the heater may be cheaper than the new fish.


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