Water Temp Not Going Up?

[Byron]

I didn't mention room temperature previously because I didn't realize it was an issue here.  But no heater should be expected to heat an aquarium if the room temperature is more than 10 degrees below the desired tank temperature.
 
Aquarium heaters are not designed to heat very cold water up to a tropical temperature.  They are intended to heat an aquarium slightly above the ambient room temperature.  I have my seven tanks in a dedicated fishroom, and it is at the end of the house and was an addition by a previous owner, so it has its own baseboard heating and not part of the main house furnace.  In the winter, I keep the room around 70-72F, so the tank heaters work to maintain the tanks around 76-77F.  If I allowed the room to cool it would easily be around 60F (the rest of the house can reach this during night as I do not like the furnace on at night) and this would be too much for the tank heaters.  This can cause them to malfunction, as they are being expected to do more than they are designed to do.
 
If the room temperature really is a major factor, two tank heaters are essential.

 

[nick1986]

room temp is fine at the mo about 20-22 ish and only going up 5c at the most.

 

[Byron]

I would worry about a heater that is set at 32C and the water remains 25C, when the room is 24C.  The tank will not be cooler than the room, unless the room cools and then reheats obviously, as the tank temp would also lower but more slowly than the room, and then take longer to reheat.

 

[RainboWBacoN420]

I never even would of thought that a completely colder temperature would over work the heater. I think I've ran into this situation when setting up my 55 back in July. I filled it with cold water and turned the heater on and it took days for it to warm up. Again, I'm using a 200 watt Hydor. And Temperature is always 10 degrees more than the set temperature, so when it did warm up, the tank was almost 90 degrees Fahrenheit.
 
As for heaters that are inaccurate with the temperature set, I've used Aquatop's heater for my quarantine tank, and the results have been accurate with set temperature. In my 15 gallon as well using a different heater, I'm not sure which brand, I'm pretty it's TopFin's heater because it came with the tank in a kit.

 

[Fishmanic]

you need a dependable heater of the proper wattage for the tank...  A very important note is that wide swings in temperature over a short period of time can cause your fish to develop ich--which is disastrous for your fish.  I speak from experience as I had a heater fail and didnt replace it for a few days but just had a space heater pointed at the tank.  That was not sufficient to properly heat the tank and I lost about half of my fish (lost about 8)  due to ich.     

 

[nick1986]

Yes think will be getting a 300W heater and I'm going for the Fluval  E300 getting it ordered on Friday think that can be my xmas present from the kids lol

 

[boshk]

I have the 100w Juwel one that came with the tank, goes inside the filter box. I set it at 28C and water temp is 27.5C, room temp dropped to around 13C a few days ago and it manage to keep it at 27.1C. 125L tank (34G)
 
might want to get it checked.

 

[nick1986]

thanks got a 300w fluval e300 on order now so think it will come after xmas now sure it will work better than the one that's in at the mo.

 

[nick1986]

hi just an update iv had the E300 from Fluval for jusat over a week now and I have to say I'm made up with it keeps the water within +/- 0.5 C always in the green and I do have an other digital thermometer that shows about the same temp. looks good in the tank only thing I can say is every so often it will come up with LF (Low Flow) I do nothing don't move it or anything and it sorts itself out. comes up about 1s a day don't know why its in a high flow area. 100% better than my last one.

 

[Byron]

hi just an update iv had the E300 from Fluval for jusat over a week now and I have to say I'm made up with it keeps the water within +/- 0.5 C always in the green and I do have an other digital thermometer that shows about the same temp. looks good in the tank only thing I can say is every so often it will come up with LF (Low Flow) I do nothing don't move it or anything and it sorts itself out. comes up about 1s a day don't know why its in a high flow area. 100% better than my last one.

 
Nothing to worry about, I have two of the Fluval and in the 70g tank the LF also appears, yet the heater is directly in the flow from the filter (in both).  In my 115g the filter puts out a real blast whereas the 70g is under the much softer flow of a spraybar.  I've had these for over three years now with no issues, so I ignore the LF.

 

[OldMan47]

Note: I have not read this entire thread.
There is no value of heater that fits a particular tank temperature. What your heater needs to do is raise the water temperature above the surrounding air temperature. If you keep your home at say 19ºC it will take a much larger heater to get your tank to 25ºC than if you keep your home at 21ºC. You need to judge what heater you really need based on your results in your situation. Heater brand matters not at all in how much heat you get, but some heaters are a bit more reliable than others so that may enter into your decision. Never rely on the setting values because they are notoriously inaccurate. Instead set the heater where you think you need it and then adjust using a thermometer.