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.

First one I received was heating so high above the set temperature that I maxed out the calibration adjustment and it still had to set it two degrees colder than the actual temperature (I had it set at 73 but the tank temp was at 75). I figured I'd just keep it like that, but then like 3 or 4 days later the temp suddenly started dropping, to the point where I needed to crank it up to 77 to keep my tank at 75. At that point I returned it for a new one. I've been using the new one now for about three or four days and it's working perfectly. Calibrated it the day I started using it and it has held the correct temp since then. Will update this review if anything changes. 12/24 - downgrading to 3 stars after using for a while. Yesterday I tried to bump the temp from 75 to 76 which seems like it should have been straightforward. Moved the dial 1 degree warmer but tank heated up to 77. So I dialed it back about 1/2 a degree and it stayed at 77 (heater was still kicking back on when temp was at 77. Then I moved it down again maybe 1/2 degree or so, and it then wanted to stay at 75. After fiddling for a while I think I finally have it stable at 76 -- with the dial reading 75. Seems like this should not be so hard. Halfway through all this I remembered the directions saying to unplug before adjusting the temp, so I started doing that -- but it didn't seem to make any difference. This thing has me stressed out. 6/24/22 - After 6 months of working perfectly to keep my tank at 78 degrees, today suddenly the temp is at 79 and holding steady there. I hate this thing. Downgrading from 3 stars to 1.

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.

After a few time-consuming and tedious back-and-forths with heating, this is consistent and accurate keeps the temperature at the specified mark, is slim and discreet and never looked back after getting it. Not sure about the thickness as it has not broken but it is comfortable and safe to touch as a working heater should be. Would recommend.

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.