Eheim Jager Thermostat Aquarium Heater

First things first, turn the temperature down, and wait. It's important to calibrate the heater before you set it or assume that 77°=77°. I found that the heater is much hotter than the calibration it comes with, and seeing the other comments I would say it's safe to assume that they are mostly all this way. You will need a separate thermometer to calibrate the heater. This is an easy fix, just follow the instructions provided! My 1 complaint is that this heater is very bulky. I thought the glass would make it seem more discrete but I may need to look for another one considering I have a 5 gallon tank. (recently added mopani wood causing the tea-colored water)

I bought this heater 3 months ago and right off the bat I wasn’t happy it always fluctuated 1-5 degrees and now just recently I checked my temp and it was 72 degrees. It just totally stopped heating even though the light was on!

The heater itself works great, however it was missing one of the suction cups. I know that sounds minor, but it didn't want to stay submersed without it. I was able to make a suction cup I had work.

After I purchased this heater and noticed the aquarium seemed a lot warmer than what my other aquarium is (set to the same temperature, different heaters) I brought out a thermometer and found out that this heater is holding the tank right where I want it, vs my Fluval E’s holding the tank 6 degrees low. Here’s where it’s lost the star; the knob is quite difficult to turn at times.

I’ve been using this heater in my 10 gallon betta aquarium and it works wonders! The only issues I have experienced thus far is the turning of the temperature knob is rather hard, you have to use a lot of pressure. Another issue I have seen is that the temperature set on the heater doesn’t match the number on the knob at times. Other than that, it’s slim, holds temperature exceeding well, and is better than any other heater I have used in my years of fish keeping!

First order, the heater didn't work at all. Chewy promptly sent me a new one. Second one worked but it absolutely sucks. I'm only trying to keep a 10 gallon tank at 80 degrees and the temp is all over the place! Sometimes the temp is as low as 69 degrees. The room tank is in is cold but that shouldn't matter. I finally had to put my cheap aqueon heater in that came with my tank kit so the tank stays at a stable 75 degrees. Even with the assistance of the second heater, it still can't bring the temp to 80 degrees! Very disappointed. Chewy customer service gets an A++ as always.

This heater is great and the other Eheims I have had in the past worked great and I have never had one wear out. This one has updated features. Yoy just set the correct temperature and put it in place and it holds that temperature perfectly with no need to make adjusts at all.

I’ve tried multiple brands of heaters and they never worked. If you follow the instructions to set this heater up it’ll work great. I totally recommend this heater. I would say get a bigger wattage because the chart is not right. I have to turn the temperature up all of the way because it’s not strong. It keeps her water at a great temperature tho. Not too hot and not too cold.

I have a 40gal Tall tank so it's a little long for the tank but it keeps my turtle nice and warm. the only complaint I have about the product it the way it suctions onto the tank the suction cups and the plastic piece connected to them don't stay in place very well.

Very easy to read. Holds temperature perfectly. Have the same heaters in other tanks and never had a problem.