EheimJager Aquarium Thermostat Heater 100W ( Pack of 1)

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.

This heater seems very well made compared to other glass heaters. I've had much more expensive heaters which failed prematurely as well as cheaper ones that have lasted many years. It really seems like a coin toss when buying an aquarium heater. I bought this one based on reputation and reviews.The temperature was dead-on right out of the box, but I like that it can be calibrated.EDIT: 2 years later it still works perfectly. My only complaint about these heaters is that they are huge and not easily concealed in the aquarium. I've tried replacing it with smaller stealth heaters, but each one of them (5) failed, so I've kept using this one even though it's ugly to look at in the tank.

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.

I have 3 separate thermometers that all show 81 degrees when this is set at around 77 degrees. I first thought the problem was this heater but I now realize it is my LED light that is heating the tank to 81F. Other than that it seems ok. It is long. Longer than any fish tank heater I have ever owned. Read the description before you buy it. I have to put in sideways in my tank because it is so long.

My fishes love this. They're more active than ever since I changed the heater. I love that you can set the temp and it stays that way

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.

Bought this for my turtle tank. I have purchased several others and they did not work, this one seems to be holding up very well.

I previously had an Aqueon 100W heater which I purchased at the beginning of 2022. After multiple failures and warranty replacements I decided to move on and try this Eheim heater instead.First I will mention that I have a 20 gallon long tank and this thing is huge and does not fit vertically. I have it horizontal in the tank.Next, with the dial set to 78F, it heated my tank to 82F. I turned the blue dial to 74, but it still heated to 80. I followed the calibration instructions. I wanted my tank at 78F and to get there after calibration it needed to be set to 75ish.As long as it maintains the temperature at 78F and does not quit working I guess I will be happy.

I've been using this brand of heater for years. They are reliable and work great. Amazing price too. Cheaper than cheapo petsmart brand heaters.

Es de origen aleman no chino buena calidad

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.

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.

So far it’s working great I have waited for at least a month of continuous use before making a review and so far it’s good. It makes sense because it’s made from Germany. Should be a good quality. Also you should have at least a foot deep of water to use this because it has to be standing.