Tetra 26446 HT Submersible Aquarium Heater With Electronic Thermostat, 100-Watt, Multicolor, 10-30 Gallon

I've had to replace this heater once after a couple of years but it otherwise does its job effectively.

I have a few of these in use and haven’t had one fail yet. Most mainstream brands still use bimetallic strip thermostats in most of their aquarium heaters. These Tetra heaters use an electronic thermostat instead, which should reduce potential failure points by eliminating both the moving parts of a bimetallic strip, and the temperature control knob, which is a point on other heaters that can allow water ingress. On paper, that makes them a bit more robust than the traditional design.The main drawback is that these are fixed to around 78°F. If you need to run a tank hotter—into the mid-80s for disease treatment, for example—these won’t do the job.That said, for most people and most setups, these heaters are perfectly adequate, especially at the price point.If you need more flexibility or want extra peace of mind, I’d suggest looking at some of the heaters from Chinese brands with external digital controllers. Even better: pair your heater with an external temperature controller. That way, both the heater and the controller would need to fail at once to overheat your tank. Ideally, you’d run two smaller heaters, each on its own controller, to provide redundancy for both stuck-on and stuck-off failures.Of course, by the time you buy all that, you're looking at a setup that costs about six times more than one of these.So it really just comes down to where you want to land on the cost vs. risk spectrum.For a basic, inexpensive heater, these have done the job just fine for me.

This is a plug and play device. No adjustments or calibration required. Got the tank water up to temperature quite easily and has been maintaining it consistently. My Oscar’s seem to enjoy being close to the heat. Also great value for the cost.

I bought 2 of these for my betta tanks, they are both around 5 gallon, the fish always seemed to be sluggish and laying around on the bottom of the tank. I read they liked slightly warm water so I bought these after checking pricing at my local pet store. The same exact one at Meijer was double this price, which worried me if it was going to be decent.I plugged them both in , obviously one in each tank, attached the suction cups, there was nothing to adjust at all, the red light came on saying it was working, after about an hour it turned green which meant it had reached proper temp, I felt the water and it was not really warm but more slightly warmer than room temp. But before it was quite cool to the touch, almost cold. Within less than an hour later both fish were swimming all over the place.This was 4 days ago and it although it still is early I have to say this was a great buy. The fish continue to seem happier, more active, eating better, cant believe how much a difference it made.So far , so good. I love my fish, dumb I know, but bettas are so unique and have personalities I'm just sure of it, lol! I feel like a much better fish owner having got these heaters and making the fish more comfortable, and I could swear their colors seem brighter, a side effect perhaps? This is a great price , it works like it said it would and it adjusts the temp in the water automatically. I cant complain at all about this product.

Small but works good. Temp is accurate.

Got this 2 weeks ago and was thrilled that it kept my 3 gallon tank warm and my betta happy... until it stopped working last night after I cleaned the tank and changed partial water. It stopped working all together and water is ICE COLD this morning! The light is green and will occasionally turn red for a few seconds before going back to green (which is supposed to indicate the the water is at the correct temperature). Still cold. I called Tetra customer service after reading many of the reviews here with the same issue. I explained what happened and asked if there is anything I could do to fix it or reset the heater as another reviewer mentioned that customer service gave instructions which fixed the issue. The customer service rep I spoke to would not help or even talk to me further if I could not tell him the temperature. I explained that I do not have a thermostat therefore I wouldn't be able to check the temp but I assured him that the water was noticeably cold to touch in comparison to the warm water that has been consistent in the tank in the 2 weeks I've had this heater and tank. He rudely continued to cut me off and said that he couldn't help me if I don't have a temperature and he became more and more condescending in his tone has he continued. His customer service was TERRIBLE! I told him that I understood he needed to know the actual temp and that he couldn't trust the temperature based on touch, so I asked if he could at least tell me what the possible options are as far as fixing this issue would be as I saw many other amazon reviewers shared the same issue. He became increasingly frustrated, increasingly rude, saying that he needs the temperature to know if he needs to send a replacement etc. I graciously explained that it was not my intention to get a replacement. I just wanted to know if he could help me troubleshoot so that I can attempt to fix my heater before my betta dies. I'm not interested in waiting for a replacement heater to come in the mail. Eventually I just asked to speak to his supervisor multiple times before he finally he basically said (like a child with a bad attitude) "Fine....." and he patched me directly through to someone's voicemail. I WILL NEVER PURCHASE TETRA PRODUCTS for the simple fact that customer service is NOT a priority to them. A simple "I'm sorry you're having trouble with your new heater. Tell me what's happening and let's see what we can do...." would have been great and I would be willing to go to the nearest pet store and buy a replacement myself if he was willing to help me troubleshoot and exhaust all options first. Instead, the gentleman has no customer service training, does not know the meaning of showing empathy, and is not interested in helping anyone... unless you can tell him the temperature of the water even though this heater doesn't have a thermostat in the first place.

Excellent product!

I have a 4 gallon tank this is a bit big but, keeps the 78 degree temp. I had a 50 W heater, small in size, it did not keep the 78 degree temp. Would would like to have the option to buy another color, white.