EHEIM Jager Aquarium Thermostat Heater 50W, Black

I have bought this heater many times and for various sizes of tanks. My oldest Eheim heater is a 300 watt in a 75-gallon freshwater aquarium and has been running for 4-years. For this reason, I decided I needed to replace this heater before it goes bad and that is what prompted this review.The only issue I have is that the thermostat is sometimes off a few degrees even after following instructions and setting it properly. Because of this, I found it easier to monitor the temperature with a separate gauge and if the temperature exceeds what I want within the tank, then I twist the dial down a degree or two. Also keep in mind that the lights over your aquarium will heat the water a few degrees so it's best to do this with the lights off.Some of the older reviews for these heaters mentioned overheating. If you're also worried about this, you can buy thermostat controllers that come with a probe you place in the water and when the temp exceeds the temperature you set the controller will turn off the heater. Inkbird makes a very reliable and cost-effective version of this called "Inkbird Freshwater Saltwater Aquarium Heater with Probe Thermostat".Overall, I have been very happy with the reliability of these heaters. When paired with a thermostat controller as mentioned before you should never need to worry about this heater overheating your tank.

I’m not one to really ever write reviews on something but here we are! Long story, short, I tried four heaters before this one. Anyone who does anything with aquariums knows besides lighting, heaters are one of the more stressful things. The other four heater brands I have tried had burnt on either one or both sides. Regardless if I turned the heater off, unplugged it and let it cool down before a water change. One of them burnt just because. Thankfully, there are no fish in my tank yet. I came across this heater and it’s been my saving grace honestly. Incredibly accurate! I love that the heat it puts out is pretty equal in every place of the tank. If you are looking for an accurate, reliable, easy to use heater, this is the one. And you cant beat the price. I wont go back to any other heater.

I have been using this heater in my tank for over 3 months without any problems. It maintains the temperature and holds it accurately as per the temperature indicator as long as you provide enough circulation in the tank to move the water around. I did not have enough circulation even though I kept the heater near the filter outlet and I never used to get the correct reading from my digital thermometer sensor on the opposite side of the tank back wall. Adding a small power head to circulate the water in the tank fixed this.Here is what I didn't like about the heater. The instructions that come with it are a little vague and it is not very clear when it comes to calibration and setting the temperature. You have two dials to work with - the blue one is the dial for setting the temperature which is indicated by an arrow on the second red dial which is the calibration dial. I had to go through a lot of trial and error before I got it right but here is what you will need to do. By default when you get the heater, the red dial should be pointing to the opposite side of the power cable that goes into the top of the heater. Leave it like that. Turn the blue dial to the temperature you want and install the heater in your tank and plug it in. Note that there is a minimum water level indicator on the heater, make sure it is stuck into the water at least till that mark. It can be submerged completely as well. Make sure you have plenty of water circulation around the heater to move the heat around the tank. After an hour or two, check the temperature on your thermometer. It should ideally be what you set the blue dial to. If it is not, you will need to calibrate your heater by just turning the red dial to point to the temperature reading on your thermometer, and then turning the blue dial to again set the desired temperature. My heater finally settled down to the default position of the red dial. Just make sure you get the right heater for your tank size to avoid calibration issues.The thing that I hate the most about the heater for which I did not give it 5 stars is because the blue dial is just too tight to turn. There is no way I can turn it with one hand when the heater is sitting in its mount in the tank. I have to take it out, hold the heater with one hand and then use force to turn the blue dial and then put it back. I hope this design will be improved in the future.

Works Well and lasts!