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Eheim Jager 100w can't heat 80liter tank

Jack Reilly

Jack Reilly

Member
Joined
10 Jul 2016
Messages
143
Location
australia
My eheim heater has been struggling to keep the tank at even 24 degrees (I'm aiming for 26). Currently having to run it at 32 degrees just to keep the tank at 24 (calibration dial wouldn't go any further ). Is my eheim faulty or what?

My 100w hydor kept the tank at 26 easy... And if I adjusted it up or down the tank temperature adjusted with it. I thought eheim would be superior but this thing is junk. Is 100w not sufficient? Anyone have any similar issues ? Screenshot_20170716-143951.png Screenshot_20170716-143958.png
 
I have no personal experience with Eheim heaters, but with the once i have experience with (several brands) i find 100 watt for 100 litres a bit on the low side anyway. Maybe for a summer periode with a pretty warm ambient temperature it would be sufficient but in cooler seasons it likely will be even more problematic. I noticed a 80 watt having trouble keeping a 50 litre on 25°C with a 15°C ambient temperatur and replaced it with a 125 watt.

I looked it up and Eheim surpisingly doesn't specify any of this data, which i rather find dissapointing from a brand like that.. For example Eden 425 serie heaters specify this very clear in the data sheet and state a Delta Temperature. For example if a 100 litre with a Delta T of 15° C you need 200 watt.. 100 watt will unly suffice for a 10°C temperature difference.. What next to that still can differ with the amount of turn over in the tank and or if it is open top or closed. That makes it somewhat difficult to say if the heater is faulty, as we also do not know how eheim tested it to get to their numbers.

Depending on the fish sp. (i also sellect my fish on this data) i rather keep my tanks a bit cooler +/- 22°C and still have 150watt (2x75watt) in the sump of my 100 litre tank.

Also experience inline heaters being more sufficient than in tank heaters. But in all those years i never encountered a heater beeing spot on accurate with the given specs. That's just beeing lucky i guess.
 
Sounds faulty but heater efficiency is significantly affected by ambient temperature, eg, in winter my house may run 59 - 64F, 150watt Eheim has no difficult maintaining 76 - 80F for 210 litre tank (heater dial set close to these temps)
Having had one heater stick "ON" I always run tanks with lower power heaters

Check the calibration (see instructions for your model)
 
The room is 17 degrees at the moment (winter) so to get the tank temperature to 26 it would be raising it 9 degrees above room temperature. The manual does state that eheim recommend the 100w heater for tanks up to 150liters based off ambient room temperature of 22degrees. But as my tank is half that size I thought it would be sufficient. But interesting that zozo pointed out the Eden says 100w can only push the temp up 10degrees.

What's surprising is that the 100w hydor inline heater can change the temperature of the tank rapidly (I was using this last week in the same room) while the ehiem seems to be struggling to even maintain 24.
 
Yes and that is an average assumption of standards, and what these are remains a mystery, non of the heaters explain how they come to them. As glass thickness, flow, open top or closed and ambient temperature are all factors having influence on the heaters performance.. Next to what stands 100 watt for, obviously in the first place power consumption and not realy accurate capacities. As you experienced yourself a 100 watt hydor seems much more sufficient than a 100 watt eheim. And both consume the same amount of energy well in operation.

What maybe could help is placing the heater in another spot where flow is optimal.. Could be the heaters thermostat switches off while the other end of the tank still isn't at the set temperature. It likely is the build in bimetal thermostat (which are known to be very inaccurate) playing your parts, using a external electronic digital thermostat with the heater set 2 degrees higher than desired temp and do the rest external could also result in a huge difference. The inline hydor also uses an digital thermostat.

Digital thermostats can also be calibrated to the thermometer in use..

Another thing to keep in mind is the thermometer.. I have such a hangon liquid filled thermometer sold by one of the sponsors, which says 18°C while another digital thermometer says 20.9°C and the digital TDS scanners thermometer says 22°C.. That's quite a discrepanty all stating beeing very accurate in the manuals description. o_O Seems each manufacturer has its own concept of accuracy. In reality with the 4° difference i measure with 3 different meters i do not know what temps my tanks are other than warm enough since i have no issues. :)
 
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