Ehiem 200w heaters calibration and recalibration

[Salucam]

Do aquarium heaters need regularly recalibrated?

I have 2 200w Ehiem Jager heaters on my 75 gallon tank. During the summer they were calibrated to 78. According to my thermometer the tank slowly got colder as the temp went down outside (I live in ohio) I assumed this was normal but once it dipped under 74 degrees I decided I had to get bigger heaters. As a last ditch effort I turned my heaters up they now stay on and my tank is back up to 76/climbing. I’m monitoring to ensure they don’t get too warm and will recalibrate when they hit 78.

Feels like a dumb question but I couldn’t find anything about needing to calibrate for different times of year online. Will they stay too hot when summer rolls around ?

 

[Uncle99]

If you experience seasonal changes, your tank might experience the same in terms of higher to lower temps or vice versa.

My tank runs 1/2 degree hotter overall in the winter because the furnace is on, 1/2 to 1 degree cooler in the summer months.

Since the temps are stable after change, I do nothing.

 

[braaap]

For some reason Eheims are always 2-3 degrees off. How are you measuring tank temp? Just a standard thermometer? How do you know it is accurate? I set my Eheims at 79-80. My tank holds steady at 77.

 

[Salucam]

For some reason Eheims are always 2-3 degrees off. How are you measuring tank temp? Just a standard thermometer? How do you know it is accurate? I set my Eheims at 79-80. My tank holds steady at 77.

You are a lifesaver. I was trusting the thermometer that I bought when I put the tank up which had always been accurate. After double and triple checking from other sources the tank was sitting at about 82. Going to get a more reliable thermometer. Thank you for saving me from my lapse in common sense.

 

[braaap]

You are a lifesaver. I was trusting the thermometer that I bought when I put the tank up which had always been accurate. After double and triple checking from other sources the tank was sitting at about 82. Going to get a more reliable thermometer. Thank you for saving me from my lapse in common sense.

Glad I could help. Order a digital one off of BRS. The JBJ Digi-Temp is decent and cheap. Or just get an inkbird.

 

[redfishbluefish]

The other consideration with heaters is the hysteresis...the lag in temperature rise and fall...which might change from season to season. However, my reason for commenting is that I would strongly recommend not relying on the temperature sensors in the heaters, but rely on a separate controller. You set the heaters to be a little higher than the temperature you want and have the controller turn your heaters on and off. The reason for the controller is that every heat will fail, with the most common failure of the heater being stuck ON.