Why temperature swings 1 - 1.5 using my heater?

[scallop]

Usually water circulation is the culprit when heaters overdrive and heat the tank. I know I had this problem on a 6-gallon nano reef. I fixed it by placing a powerhead directly across from it aimed at the middle, right above the coil. This is where the thermostat usually is. If this does not solve the problem try a different heater. Good luck.

 

[pestrada]

I actually have the heater submerged (upright) inside my hang-on whisper filter. It gets very good water circulation.

I do think that if it was a water circulation problem then the heater would shut off much faster because it would heat the water around it quicker, thus making it very unefficient.

 

[Bucktronix]

i think the key words here are "made by Hagen"

 

[fsa]

Years ago,I had that problem. Found out the heater was rated too large for size tank I had at the time. Bought a smaller heater and never had that kind of swing in temps again.

 

[MattM]

It's not because it's "made by Hagen". The Tronic heaters are very good - we've been selling them for over a year now and have not had a single one returned.

What you are seeing is normal. It's called "hysteresis". The heater is intentionally built to have a 1 to 1.5 degree swing between the on and off points. So it turns on at a little below the set point and it turns off a little above the set point. If it wasn't built this way, it would cycle on and off very rapidly at the set point and quickly break.

Any self-regulating feedback system is designed this way including the thermostat in your house. Again, if it wasn't the AC or heater would wear out by rapidly turning off and on all the time.

 

[pestrada]

I have setup a new 10 gallon micro reef and installed a new Tronic 50W heater (made by Hagen). I have the heater set to turn on at 77, but I have noticed that when it turns on, it drives the tank's temp. to about 78 before shut off. The heater will not turn on until the temperature drops back down to about 76.6.

Is this temperature on/off range normal for these heaters? I don't recall having this much of a temperature fluctuation with my past larger aquariums.

Thanks.