New to Heaters and Is Mine Working Right?

I just bought this Hydor submersible 50W heater for my 5.5gal yesterday, because winter is about here, and I don't want my fish to get sick or freeze. However, seeing as there is a seemingly endless number of horror stories about heaters on the Internet, and I don't know what is "normal" for a heater, I'm posting this thread. Here's two things about my new heater:

- I have tested the heater in an empty 1gal fish bowl, and even though I set it to 73F, the temperature rocketed to 80F a few hours later. (is this because the bowl is 1gal and the heater is for 5-14gal?)

- The heater has a light that turns on when the heater starts working, but right now it's turning on and off in short intervals of time (about 1 min in-between).

Are these normal for a 50W heater in a 5.5gal tank?

 

If your testing it with a 1 gallon, I think for efficiency it has a built in timer for the gallons it was designed for and when it turns on it heats the water very quickly because of how much energy is dispersed.

 

For the heater to turn on and off is normal, provided that it has a thermostat on it(most should), it will switch on when the temperature gets below the set temp, and turn off when it warms to the set temp. Does your heater have an adjustable thermostat? I have a 100Watt tetra heater in my 20 gallon quarantine that has a set thermostat, kicks on when it gets to 77 and turns off at 80. It will come one for a minute or two every hour or so.

The higher the wattage means the quicker it will heat the tank. It shouldnt go past the set temp. If its non adjustable, look at the instructions to see what the temp specs are.

 

The higher the wattage means the quicker it will heat the tank. It shouldnt go past the set temp. If its non adjustable, look at the instructions to see what the temp specs are.

I set the heater to 70F this morning and put it in my actual tank (5.5gal), but by 2pm it is 76F...so does that mean I have to go return this heater now? Also, I unplugged it a minute ago, set it to 65F, and plugged it in again, and right now it's still going on every 1 minute or so.

 

Thermostats on adjustable heaters are more of an estimation of the temp achieved. You may have to turn your heater to 65-68ish to achieve the real temp of 70. Smaller tanks can be hard to heat as the smaller amount of area leads to more fluctuation than you would get in a larger tank that is more temp stable.

Basically, disregard what the dial temp says on the heater, just keep adjusting it until you get your water temperature to the point you want it. Also be sure you are using an accurate thermometer to check, or maybe even 2 thermometers. I like having 2 just as a double check.

 

Thermostats on adjustable heaters are more of an estimation of the temp achieved. You may have to turn your heater to 65-68ish to achieve the real temp of 70. Smaller tanks can be hard to heat as the smaller amount of area leads to more fluctuation than you would get in a larger tank that is more temp stable.

Basically, disregard what the dial temp says on the heater, just keep adjusting it until you get your water temperature to the point you want it. Also be sure you are using an accurate thermometer to check, or maybe even 2 thermometers. I like having 2 just as a double check.

Thanks for the advice, I was suspecting the heater may not be so accurate like it says. I guess I'll keep adjusting the dial, but if the temperature still keeps going up beyond 78F, I might just go back to LFS and return it.