EHEIM Jager Aquarium Thermostat Heater 100W ( Pack of 1)

One of the best quality heaters out there! Easily set the dial to your preferred temperature and you’re good to go. I choose these because I like how consistent they keep my water temperature.

I’ve been using cheap tetra heaters for a while but had to retire them, so figured I’d try Eheim. It’s ugly and I can see it shining through from behind the plants (it’s pretty thick foliage too), but right out of the box the temperature was spot on. It does fluctuate a bit at night and at the warmest part of the day, but it’s only by 0.2 to 0.4 degrees so I’m cool with that. Just know it’s gigantic and very shiny so it’s not for aesthetics. It’s a beast of a heater, more than twice the size of a 100W tetra heater. I will update this review when I have to replace it.

A very classic style of submersible aquarium heater. Heavy duty cord, temperature controls are nice and stiff but the dial indicator is a little chunky. The user manual does state that it’s not for use with a secondary thermostat but I use mine set to about my max temp and then use an Inkbird set to control the the on off cycle at my preferred operating temperature . I gotta give the manufacturer credit for the packaging, Amazon packed this glass heater with a 15lb bag of gravel and the post office beat the box like it owed them money, yet the only thing broken was one of wings on the disposable plastic packaging stabilizer.

Quality, dependable, consistent heating. German engineering gets it right again. Picked up another for a backup just in case and have a temperature alarm. 3 years strong. Only knock are the suction cups not holding as well over time on occasion.

Product works great. it runs a few degrees warm in my tank (set to 75, reading 78). Its been going strong for over a year now. It was a lot longer than expected, and I had to put it in at a slant on my 40 gallon breeder.

I've had good luck with name brand pet store heaters over the years but I just bought Discus which are very expensive and "delicate". I didn't want to take the chance on the heater already in the tank as Discus need consistent warmer temps & the old heater is one of those preset ones with no ability to increase temps if needed. My house isn't heated so with winter coming on and night temps already in the lower 50s I wasn't going to take a chance on losing my new high priced fish. EHEIM is a well respected German aquarium product manufacturer and the reviews on this heater were excellent. The instructions are in more languages than I bothered to count which tells you this company is used world wide by aquarists. Some reviews mentioned temp setting dial not being accurate but I monitored mine continually for 2 days with multiple thermometers to be sure it was the temp I set it for with no issues. I only bumped the temp up a few degrees from what it was with the old heater but the fish demonstrated that those few degrees were exactly what they needed. Excellent color & activity in their new home including good appetites which can be an issue with Discus.

I used to use a different brand, I think it was Tetra but their heaters got bought by a different company. So I decided to go with this Eheim. Reason are is because it's just a simple heater. I didn't want a microprocessor controlled one because in my opinion, it's just more stuff that can break. The other reason was because a heater (once again in my opinion) is probably one of the (if not THE MOST) important accessory in your aquarium and should be something of good quality. I've had friends that went cheap on heater, and of course over time, they failed to the point where they were stuck in the heating position and cooked most of the things in their aquarium. Oh, and it was less on here than at the "P" stores. The Tru-Temp feature is pretty cool, so you can adjust the arrow to make the dial more accurate. I compared this heaters temp to a Fluke thermometer and it was .3F off from the factory position. Which for me is more than good enough. So yeah, I highly recommend this heater to anyone that wants a good heater.

Calibration is horrible. You shouldn't have to calibrate a darn heater you should be able to set it to the temperature and it heats to that temperature. This heater failed after a couple of years and cooked my tank!

Heater was delivered the day after I ordered it as expected. It comes well packaged and even has a plastic ring around the bottom of the tube to protect it in transit. I would have liked it if the cord was a bit longer. If you have your electrics hidden in a cabinet like I do, you need the cord to be able to go down the back of the tank, down the back of the cabinet and then into cabinet to where the extension socket is. If you don't have your aquarium right next to a socket, you are going to need an extension. Some people wonder why this heater 'needs' to be calibrated. I think that the truth is you don't really need to calibrate it, you could just set it to a reasonable temperature depending on your stock and then check the temperature with a thermometer for the first 24 hours or so, adjusting up or down as necessary. I think that the reason for the calibration wheel is that it enables you to set the exact temperature (in half degree increments) regardless of the ORIENTATION of the heater. Most people will hang their heater diagonally, the instructions for this one say to place it vertically but I have heard of people placing it horizontally as well (to hide it behind plants for instance). You can imagine that depending on orientation, the the thermostat might read the ambient water temperature slightly differently. The other thing that I like about this heater is that it seems to be a bit more efficient than others I've looked at. I used the 100w model to replace a 150w Fluval model that exploded as I removed it from the aquarium (never do a water change without turning off your heater first!) Looking at other models of heater, a 150w model was suggested for my 129 litre tank. In this range, the Jager 100w seems to be enough. Not sure how this is possible, but it seems to work fine. Perhaps the heater is cycling less and that can only be a good thing in terms of the stability of the water temperature and the longevity of the heater.

Muy buen termostato llegó muy bien empacado protegido recomiendo al vendedor gracias

Awesome. That is all. Great product. Works well, temp is consistent (measure with digital thermometer). Best part thus far...if i forget to unplug when cleaning (water lowers) it senses low water and doesnt turn on. Will buy more in future (bigger tanks)

Living up to the company's reputation, the heater is efficient, durable and long-lasting. The holders, cord and instruction manual are also world class. There is a thermostat dial at the top, where you can set the temperature to a particular point. Note that you'll also need another thermometer separately to be sure of the accuracy. You'll need to adjust the settings per your second thermometer, which you can buy at affordable prices separately. One of the best features about such a high quality heater is that the temperature variation is very smooth, thereby not stressing out the poor fish. Important note - aquariums should NOT be set at a higher temperature (beyond 28-29C) because it raises the metabolism of the fish, thereby decreasing its life span. After a day or two of observation, I removed this heater because the city in which I live is usually warm. If I have an aquarium in Ooty or Bangalore, I might consider using this heater to maintain the temperature at around 27. If the surrounding temperature is beyond 27, you can turn this off.

Using this product for my 20g tank. Added Eheim heater in my aquarium for more than 2 month now, and so far No big fluctuation to temperature I set. Eheim is such a good brand. I can trust the heater, mind free on worrying about my tropical fish get ill/die due to temperature changes.