Temperature Problems

[khial]

I've been having temperature problems in my main community tank (100L) for a couple of months now.
 
The heater(150 watt) is set at 28c but the thermometer says 25c.
 
1st thing I did was change the heater(another 150watt)....same problem...set the new heater at 28c and still get the 25c reading
 
So I assumed that it was the thermometer?? But no, I put the thermometer in a second tank (60L) set at 28c and get a correct reading of 28c
 
Third tank (26L) set at 28c and again a reading of 28c
 
I just cant work out why its not heating up my main tank? should i go for a bigger heater??
 

 

[Metka]

If you're finding that the temperature is correct in a smaller tank, it would leave me to believe that it just can't heat up the pure amount of water efficiently enough. Go for a larger more wattage one
 
Remember that heaters will lose efficiency the older they get - just keep an eye on the temp, a damaged one could end up boiling your fish alive!

 

[Mikey1]

the temp scales on the heater itself are very rarely ever accurate.....
 
go by what the thermometer says and ignore the heaters scale

 

[N0body Of The Goat]

Heaters need to be placed in the flow of filters/powerheads, so that the heater's thermostat is picking up a true reading of the whole tank's temperature.
 
How much heating is needed in a tank depends upon the ambient temperature of the air around the tank. My back room is normally ~24C this winter from the room's storage heaters, so I don't need to run any heaters on the five tanks currently running in there, while the one tank in the lounge does have a heater running because that room is colder and is exposed to the cool easterly winds we get during winter cold snaps.
 
Many heaters do not have well calibrated guages on them, so I'm not surprised that a setting of 28C could be maintaining 25C in reality, I have some Juwel heaters that need to be set to their maximum of ~"32C" to maintain 24C. The trick is to work out how the guages compares to reality using two thermometers in the tank (so they can back each other up as to what they find the temp to be). Some brands are better calibrated than others, my Visitherm heaters are pretty much spot on, while my Juwels underperform and my Rena Smartheaters overperform (lowest setting of 18C maintains ~21C).

 

[This Old Spouse]

I switched the heaters on all my tanks to Hydor inline heaters. Absolutely consistent. 

 

[Mikey1]

his problem is not consistency

 

[This Old Spouse]

If I set my thermostat to 73º, the water temperature is 73º. Pardon my faux pas.

 

[Mikey1]

If I set my thermostat to 73º, the water temperature is 73º. Pardon my faux pas.

 
 
thats called accuracy....not consistency....you are pardoned

 

[khial]

thanks for all the replies. yes its very consistent, but its just weird how it is accurate in a different tank,i didnt want to turn it above 30c to get the 28c i want incase i come home one day and its started "working" if you understand....

 

[Lunar Jetman]

thanks for all the replies. yes its very consistent, but its just weird how it is accurate in a different tank,i didnt want to turn it above 30c to get the 28c i want incase i come home one day and its started "working" if you understand....

Seems like Metka's advice is likely to be right. You've got a bigger tank and it's struggling to heat it. Are all the tanks in the same room? If not is the room your biggest tank is in cooler than the other rooms?

If it was struggling though is there a light on it so show when it's in operation?

 

[Mikey1]

thanks for all the replies. yes its very consistent, but its just weird how it is accurate in a different tank,i didnt want to turn it above 30c to get the 28c i want incase i come home one day and its started "working" if you understand....

 
the calibration is just off....150w on a 100L tank is way more than enough
 
dont worry about it....turn it as high as you have to to get the temperature correct on the thermometer
 
i have a 300w Eheim Jager on my 100 gallon....i have it set at about 87F and that keeps the tank consistently at 80F....

 

[khial]

yes i think i'll just go for it and turn it up,
 
2 of the tanks are in the same room,  the other one is in the dining room 15 feet away so no difference really and all have a light,
 
i think mikey maybe right, sounds like a big gap in calibration but..hey ho..never mind...will turn it up now and monitor it